Answer:
b. Carstensen's socioemotional selectivity theory.
Explanation:
According to Carstensen's socioemotional selectivity theory, individuals' perceptions of the future are limited and open-ended which determine their goals and preferences in life.
If grandparents have started focusing on things that have emotional meaning for them like spending more time with friends then these developments are more consistent with Carstensen's socioemotional selectivity theory.