Which sentence most clearly describes diction?

The answer is A

diction is the choice and use of words and phrases in writing (by the author)  

The sentence that most clearly describes diction is A. The author carefully avoids using words that are too high level.

Explanation: Diction is a term used to refer to the style of an author. In this case, an author's style is conceived in terms of word choice. Good diction is related to a choice of words that are appropriate to the context. Therefore, the sentence that most clearly describes diction is A. "The author carefully avoids using words that are too high level" since it is the only one that makes reference to the choice of words and their appropriateness. The author avoids using words that are too high level in order for the reader to understand easily what is being presented.

the apollo program, also known as project apollo, was the third united states human spaceflight program carried out by the national aeronautics and space administration (nasa), which succeeded in landing the first humans on the moon from 1969 to 1972.