Squirrels will make alarm sounds when a model of an owl is placed in their territory. When a red block the same size of the owl is placed in the territory, the squirrel does not alarm. What can you conclude from these observations?

A) The squirrel cannot see red objects, and so does not make alarm sounds.
B) The owl model, but not the red block, is a sign that triggers the fixed action pattern of alarm vocalizations.
C) The owl model is the ultimate cause of alarm vocalization behavior.
D) The squirrel is trying to attract the owl into its territory.