Answer:

Explanation:

To understand why the correct answer is option 'B', let's break down the sentence and analyze each option.

The sentence is asking the person to perform a favor of posting some letters on their way home. The verb that fits into the blank should express the act of performing a favor or doing something helpful.

Option A: Did
The word "did" is the past tense of the verb "do." However, using the past tense in this context does not make sense because the person is being asked to do something in the present or future, not something that has already been done.

Option B: Do
The word "do" is the base form of the verb and is used to express an action in the present or future tense. In this sentence, "do" is the correct choice because it accurately conveys the request for the person to perform a favor of posting the letters.

Option C: Done
The word "done" is the past participle form of the verb "do." It is used to indicate that an action has been completed. However, in this sentence, the person is being asked to perform the favor in the present or future, not something that has already been done.

Option D: None of these
This option states that none of the given options are correct. However, as we have analyzed, option 'B' (do) is indeed the correct answer.

In conclusion, the correct answer is option 'B' because it accurately conveys the request for the person to perform a favor of posting the letters on their way home.