Al Is on the Witness Stand

Al is on the witness stand. He is asked if he can remember the name of the person who told him to place the bet. Al replies that he thinks the last name of the person starts with C . Al gets visibly frustrated and says, "I know this but I can't think of it right now." Al's response is an example of

A) penultimate response.
B) feeling-of-knowing experience.
C) spontaneous generalization.
D) tip-of-the-tongue phenomenon.