Step 1: Map key phrases to theories.
- “{Mutual withdrawal of individual and society}” is the hallmark of Disengagement theory (Cumming \& Henry, 1961). It posits that reduced social interaction is a natural, adaptive part of aging for both the person and society.
- “{Positive correlation between activity and successful aging}” captures Activity theory (Havighurst), which argues that maintaining roles and social/physical activities leads to higher life satisfaction and better adjustment in old age.
Step 2: Eliminate distractors.
(A) and (B): “Decay/Balance/Engagement theory” are not the standard gerontological pairs explaining these statements.
(D) “Withdrawal theory” is not the canonical name; the accepted term is {Disengagement theory}. Though “withdrawal” sounds similar, the established label used in aging literature is {disengagement}.
\[
\boxed{\text{Disengagement theory, Activity theory}}
\]