When Developmentalists Looked at the Two Kinds of Intelligence, Fluid

When developmentalists looked at the two kinds of intelligence, fluid and crystallized, to determine if intelligence continues to grow, slow, or decline with age, they determined that

A) fluid intelligence does decline; however, crystallized intelligence holds steady and can improve.
B) crystallized intelligence does decline; however, fluid intelligence holds steady and can improve.
C) both fluid and crystallized intelligences decline with age.
D) both fluid and crystallized intelligences improve with age.