Note that the first clause is conditional and after that a subordinate clause is mentioned (which starts with “when”). Since we already have mentioned the conditional sentence, we should not mention the “condition” again in the subordinate clause (which is shown by usage of “will be”). Thus, the subordinate clause should be written in simple present tense which indicates a fact. So, in the first statement, the correct usage at the place of “will be” should be “is”. And, in the second clause, “will” should be taken off before “cover” along with “will be” before “very cold” to make the sentence grammatically correct.So, the correct answer is option C.

Note: A Type 1 conditional as in the given sentence mentions a possible condition and its probable result. The if-clause is in the simple present tense while the main clause is in the simple future tense.

The conditional sentence can be written in the two different ways. It can either start with “if+ subject + had + v3” or with the inverted form: “had+ subject + v3”. In the inverted form, “if” is not required to show condition. So, a conditional sentence can be written in either of the two forms. Also, since the past tense is used in the conditional sentence, “would” should be written instead of “will”.

Here the subject is “all the colleges” which is a non-living entity and for that “whose” should not be used. “Whose” is used for living entities. If the possession of a non- living thing needs to be shown, “which” should be used. Also, since the college is a specific ne where the “the students went on a strike”, the article “the” should be used before college. Option C is the correct answer.

Let us discuss all the sentences one by one:

I. ‘Of all’ indicates that the selection is being made from all the battles. Thus, the superlative degree should be used. Here, ‘the one’s’ means the battles fought by Genghis Khan, thus the plural auxiliary verb “were” is correct. Hence the sentence is free of error(s). 

II. As discusses above, only superlative degree is correct and the usage of comparative degree is incorrect. 

III. There are several errors in this sentence. Firstly, since the subject “battles” is plural, the auxiliary verb agree with the plural subject. The sentence is talking about all the battles fought by Genghis Khan. Therefore, “were” should replace “was”. Secondly, “Genghis Khan” is a historic human figure and cannot be termed as a human. Thus, the possession should be indicated by the usage of apostrophe ‘s’.

‘Not so much as’ is an idiomatic phrase. So, when we say something is ‘not so much a choice as a necessity’, we mean that it is more of a necessity than a choice. Thus, only alternative “II” is correct.

The first word is describing the nature of first interpretation of Elon’s behaviour. The word ‘generous’ would be a fit here which means showing kindness towards others.

The highlighted word is describing the kind of behaviour which needs to be interpreted. Thus, it cannot be ‘hidden’ and should be replaced with the word ‘peculiar’ which means different to what is normal or expected.

It can be understood from the sentence that the first word has been used here in the sense of a symbol or representative. The word ‘beacon’ should be used which means a light or other visible object serving as a signal, warning, or guide at sea, on an airfield, etc. The highlighted word is an adjective for the weight loss experienced by people due to hunger. The word ‘redundant’ means not or no longer needed or useful, and thus, does not make sense here. Instead, the word ‘involuntary’ should be used which means done without will or conscious control.

The word is the effect of certain crisis in the country. The word ‘battered’ should be used as ‘batter’ means to strike repeatedly with hard blows. The highlighted word is used for describing the level of labour strikes which were a part of the crisis that affected the country. The word ‘frugal’ means simple and plain and costing little, and thus, is out of context. Instead, the word ‘persistent’ should be used which means continuing firmly or obstinately in an opinion or course of action in spite of difficulty or opposition

The word ‘evade’ means to avoid dealing with or accepting something; and the word ‘vast’ means something of very great extent or quantity. Thus, the highlighted word fits both contextually and grammatically.

Since the overall tone of the sentence is that of hostility (because of the usage of the word ‘blaming’), ‘pleasantries’ is inapt. This eliminates option D. “Exchanging talks” is an inapt term. Moreover, “earlier” would be incorrect as to refer to the treasury (the first entity mentioned), the word “former” should be used. Thus, option B is incorrect.

Option C can be eliminated as “groups”, which has not been referred to in the sentence, will make it ambiguous. 

A ‘barb’ is an unkind remark meant as a criticism. The highlighted part should be replaced by ‘latter’ which denotes the second mentioned of two people or things, here ‘opposition benches’.