Justin, a 75-year-old man, believes he only has a few more years left. He has stopped going to the senior citizens center to play cards. He doesn't always go to holiday dinners at his relative's house. He chose to stop volunteering his time at the local theater to allow the younger members of the theater association to play a larger role. What theory does this illustrate?

A. activity theory
B. disengagement theory
C. continuity theory
D. socioemotional selectivity theory

Answer: B