Kaela, a tennis player, has been struggling to develop a more consistent serve. She made the following remark to her partner during the second set of a recent match: “I feel like I’m making progress. I haven’t double-faulted once today.” She then served two double faults, which caused her to say, “Every time I say I haven’t doublefaulted, I immediately start to.” Kaela’s perception may have been influenced by

a. The sunk cost effect.

b. Regression to the mean.

c. The availability heuristic.

d. More than one of the above are correct.

e. None of the above.