What Is the Likely Reason for Middle-Aged and Older People

What is the likely reason for middle-aged and older people being more likely to vote than the young?

A) The middle-aged person is at peak earning and the old person is concerned with Social Security and Medicare.
B) The middle-aged person is at medium earning and the old person is concerned with retiring and grandchildren.
C) Middle-aged people tend to be more highly educated and the old person is concerned with Social Security and Medicare.
D) Middle-aged people tend to live in urban areas and the old person is concerned with Social Security and Medicare.