If Monkeys Are Repeatedly Tested on Their Ability to Discriminate

Multiple Choice

If monkeys are repeatedly tested on their ability to discriminate among a set of stimuli, over several months the monkeys

A) show less and less interest in the stimuli.
B) show ever greater interest in the stimuli.
C) manifest less and less ability to distinguish among the stimuli.
D) show increasing ability to discriminate among the stimuli.