Which one of the following statements best illustrates implicit memory?

a. at age 40, after 15 years, george got on his old bike and found he could still ride it without falling on his face.
b. grace had heard the story about how, when she was three, she blew out the candles on the cake many times. in fact, she wasn't sure whether she remembered the incident or just imagined she did.
c. maxwell pondered that time, so long ago, when president roosevelt spoke on the family radio.
d. gina searched her memory and explained that if you know two angles of a triangle, you also know the third, since 180 degrees minus the sum of the two angles gives you the answer.