Which sentence is the hook in this introductory paragraph?

For the first time in decades, Baby Boomers have been outnumbered by another group—the Millennial. Baby Boomers, who were born in the '40s and '50s, are nearing or are in their elder years. Millennial, born in the twenty years leading to 2000, are now young adults. Now that they are in the majority, there are many areas where the Millennia's may impact our society and priorities.

ANow that they are in the majority, there are many areas where the Millennial may impact our society and priorities.

BMillennial, born in the twenty years leading to 2000, are now young adults.

CFor the first time in decades, Baby Boomers have been outnumbered by another group—the Millennial.

DBaby Boomers, who were born in the '40s and '50s, are nearing or are in their elder years.