The correct answer is option 1 i.e. you will water.

In conditional sentences, especially those with "unless," we use the simple present tense for the condition.

The auxiliary "will" is not used in this type of conditional statement.

The corrected sentence should read "The plant will die unless you water it every day," which correctly uses the simple present tense for the condition.

The correct answer is option 4 i.e. is best.

The adjective "best" is incorrectly used here because the comparison involves only two subjects.

In this case, "better" should be used instead of "best".

"Better" is the comparative form of "good" and is used when comparing two people or things.

The correct answer is option 4 i.e. No improvement required.

The phrase "has been sleeping" is in the present perfect continuous tense, which is appropriate here as it describes an action (sleeping) that started in the past and continues up to the present.

The phrase "for twelve hours at a stretch" accurately describes the duration.

The correct answer is Option 2 i.e. is on the 2^nd floor.

The preposition "on" is used to describe the position of something on a specific floor of a building.

"In" would indicate being inside the building but not refer specifically to a floor.

Correct Sentence:

"Our office is on the 2nd floor of the skyscraper."

The correct answer is Option 1. i.e. has gone.

The verb "has gone" is used in the present perfect tense to indicate that someone has traveled to a place and is still there.

"Is gone" is incorrect because "gone" is a past participle that needs an auxiliary verb like "has" or "had" in this context.

The correct sentence would be:

 "One of my friends has gone to Goa for a holiday."

The correct answer is Option 1 i.e. cut down.

The most appropriate word segment to replace the underlined word "reduce" in the given sentence would be "cut down".

This answer is grammatically correct because "cut down" is a phrasal verb that means to reduce the amount of something, particularly in the context of a habit or activity, which is exactly what Pintu's family doctor advised him to do.

Thus, the correct sentence is:

Pintu has been advised to cut down smoking by his family doctor.

The correct answer is Option 2 i.e. have arrived.

"Have arrived" is in the present perfect tense, which is appropriate to indicate a recent action with present relevance (the guests are still here).

The original phrase "arrived" in the past simple tense implies the action is entirely in the past, which does not align with the ongoing relevance ("they are sitting in the garden").

The corrected sentence is:

"Our guests arrived, and they are sitting in the garden."

The correct answer is option 2 i.e. am not going.

"Gone" is incorrect in this context.

The correct phrase is "going to", which is used to express future intention.

So, the verb 'gone' should be replaced by 'going.'

Correct statement: I am not going to harm this dog.

The correct answer is option 1 i.e. carefully examined.

The adverb "carefully" is required to modify the verb "examined", as adverbs describe how an action is performed.

The phrase "examined careful" is grammatically incorrect because "careful" is an adjective, not an adverb.

The correct word order for this sentence is "Viren carefully examined all the possibilities of data theft".

The correct answer is option 2 i.e. No improvement required.

The sentence is grammatically correct and logically conveys the idea.

"Can only be enjoyed" is the correct passive construction to describe the action of enjoying facilities.