First-hand accounts from soldiers fighting in the civil war were most likely communicated through what?

The choices can be found elsewhere and as follows:

A) essay written by a 7th grader in 2017
B) Letter written by a solider from the Civil War
C) A pamphlet giving facts about the Civil War
D) A speech given by the great-grand-daughter of a solider in the Civil War

I think the correct answer would be option B. First-hand accounts from soldiers fighting in the civil war were most likely communicated through a letter written by a solider from the Civil War. It is the most logical answer among the choices.

Idont understand this questio