What Is the Main Problem for Older People in Most

What is the main problem for older people in most schools today?

A) Professors often discriminate against seniors by giving them special treatment (ageism) .
B) The majority of subjects are inaccessible to seniors either because their knowledge is out-of-date or because they are not familiar with their practical applications.
C) They are configured to the goals of younger people and these rarely apply to the older person.
D) Enrolment fees are too high for most seniors' budgets.