Feathers Are an Example of A/an ________; They Originally Evolved

Multiple Choice

Feathers are an example of a/an ________; they originally evolved ________.

A) homology; for flight
B) adaptation; for some other function and only later became adapted for flight
C) exaptation; in anticipation of future use in the development of flight
D) exaptation; for some other function and only later became adapted for flight