Researchers Are Training Pigeons to Peck to Receive Food Pellets

Multiple Choice

 Researchers are training pigeons to peck to receive food pellets when they see gratings but withhold their pecks to receive pellets when they see a uniform gray circle. This procedure will help the researchers determine

A) whether or not pigeons can see color.
B) whether or not pigeons have feature detectors.
C) how much contrast a grating must have before it looks different from the gray circle to a pigeon.
D) whether pigeons are intelligent enough to learn to peck one stimulus rather than another.