Micah, who is 45 years old, remembers the time from his childhood when he went on a picnic with his family to a beach. He recalls that he was about nine years old and was wearing a blue shirt. The family swam, made sand castles, and ate sandwiches and ice cream on the beach. These recollections are part of Micah's _____.
a. Memory
b. Past experiences
c. Nostalgia
d. Personal history