Pigeons Are More Likely to Choose a More Desirable but Delayed

Multiple Choice

Pigeons are more likely to choose a more desirable but delayed reinforcer instead of an immediate but less desirable reinforcer if

A) both reinforcers are visible during the delay period
B) stimuli associated with the reinforcers are present during the delay period
C) some other,irrelevant behavior can be performed during the delay period
D) all of the above