Sam and Susan Both Celebrated Their 50th Birthdays This Year

Sam and Susan both celebrated their 50th birthdays this year. They notice that they worry now, more than ever before, about their health and what activities they will be able to continue into the future. Sam's and Susan's worries are:

A) common for people who are this age.
B) rare for people who are this young.
C) a sign of early senility.
D) affecting their basal metabolism rates.