Which of the following patterns is usually characteristic of symbolic play?

a. It peaks between 18 months and 3 years, and decreases thereafter.
b. It begins at about 18 months, and increases until about 12 years.
c. It begins at about 3 years, peaks at about 9 years, and decreases thereafter.
d. It peaks between 5 and 7 years, and decreases thereafter.

C