Answer:
I think A is the correct answer.
I think that the answer is choice A. An essay hook is usually the first or second sentences in a paragraph as it aims to grab the readers' attention. In this case, I think that the sentence that hooks the reader is: <span>For the first time in decades, Baby Boomers have been outnumbered by another group—the Millennials. Also, this statement mentions something that might be interesting for the reader. </span>
cheerful. (extra characters)
Interrupting the present story with a scene that tells about events from the past