The answer to your question would be that the sentence that uses an objective tone and formal language is A.
Explanation:
A is the sentence that has an objective tone and formal language because of the choices of words selected (<em>reveal</em>) and the facts provided to back up the statement (the percentage). What is more, the statement is not biased, it does not contain any subjective information that may have to do with the personal opinion of the author (see B, C, and D).
A. ) because its not biased. they have facts to back up their opinion. also formal language is using in text in the genres of science, math, articles, etc...
