Early research into forgetting by Hermann Ebbinghaus found that forgetting occurs:

a. slowly over a long period of time.
b. mostly between 12 and 24 hours after the learning event.
c. slowly at first, but the rate of forgetting increases over time.
d. quickly at first, but the rate of forgetting slows over time.

Answer: D

Rationale: It clearly shows that most forgetting occurs right away, and that the rate of forgetting eventually slows to the point where one does not seem to forget at all.