Answer:
The correct option is option A. Martha, could you please repay me what I loaned you a few months ago?
Explanation:
A request is commonly defined as the act of asking for something in a polite or formal manner. That is to say, a request means to politely ask a person to do something.
Request sentences often include words such as "can", "would", and "please", just to name a few.
Bearing in mind the stated above, it could be said that the most appropriate tone to be used in a letter to a friend about the repayment of a loan would be: "Martha, could you please repay me what I loaned you a few months ago?"