Why Do the Findings of the 2004 General Social Survey

Why do the findings of the 2004 General Social Survey (GSS) in Canada likely underreport the incidence of elder abuse?

A) Older people are less willing to complete surveys of a personal nature than younger people.
B) Questions on elder abuse in the GSS do not include emotional abuse.
C) Many seniors feel that there is a stigma in raising a child who mistreats them and therefore would not report abuse.
D) Older people have short term-memory lapses making recall of abuse more difficult.