Three Groups of Pigeons, None of Which Had Experience Outside

Three groups of pigeons, none of which had experience outside of its loft, underwent surgery: Group 1 had their trigeminal nerves cut. Group 2 had their olfactory nerves cut. Group 3 had sham surgery. The pigeons were then released 50 km from home. The initial orientation of Groups 1 and 3 was in the general direction of home, while that of Group 2 was in the opposite direction. In addition, 23 of 24 birds from both Groups 1 and 3 returned home within 24 hours, while only 4 of 24 from Group 2 made it home. These results suggest that

A) any type of surgery severely disrupts a pigeon's ability to home.
B) magnetic cues and olfactory cues are equally important in a homing pigeon's navigational map.
C) magnetic cues are more important than olfactory cues in a homing pigeon's navigational map.
D) olfactory cues are more important than magnetic cues in a homing pigeon's navigational map.