In Field Tests of Optimal Diet Theory, It Is Impossible

Multiple Choice

In field tests of optimal diet theory, it is impossible to control the rate at which the subject encounters prey types. When tested in a laboratory with appropriate controls, however, Krebs and his coworkers (1977) found that when large mealworms were made more plentiful, in contrast to the model's predictions, his bird subjects

A) consumed small and large prey in direct proportion to their presentation rates.
B) immediately excluded smaller prey from their diet.
C) never completely excluded smaller prey from their diet.
D) tended to exclude large prey items from their diet.