Bernard Is Now 80 Years Old

Bernard is now 80 years old. When he was 20 years old, he took part in a detailed study that assessed various aspects of his intellectual functioning. Which of the following would he most likely find if Bernard were to complete the same tests today?

A) Both his fluid and crystallized intelligence have declined over time.
B) His fluid intelligence has remained stable over time, and his crystallized intelligence has increased.
C) His fluid intelligence has declined over time, but his crystallized intelligence has remained stable.
D) His crystallized intelligence has declined over time, but his fluid intelligence has remained stable.