What Has Become a Virtual Consensus Among Researchers Studying the Effect

Multiple Choice

What has become a virtual consensus among researchers studying the effect of aging on intelligence?

A) intelligence as a whole declines considerably with advancing age
B) intelligence plateaus at age 25 then remains virtually unchanged until the 80s
C) fluid intelligence remains nearly flat, but crystallized intelligence declines sharply in the 60s, 70s, and 80s
D) crystallized intelligence remains nearly flat, but fluid intelligence declines sharply in the 60s, 70s, and 80s