Respuesta :
Answer:C
Explanation:This version uses formal syntax and diction, which matches the overall style of the passage. I also did the exam on AP classroom.
The phrases that successfully provide a formal tone to the text would be:
C). fortunately for posterity.
Formal Tone
A formal tone is described as a tone in which a very precise, technical, and professional vocabulary is used to convey an objective viewpoint on the topic.
The third phrase correctly develops an official language to the phrase by employing adequate diction and helps go with the actual style followed throughout the passage.
Thus, option C is the correct answer.
Learn more about "Formal Phrase" here:
brainly.com/question/16423853