A Male Stickleback Fish Will Attack Other Male Sticklebacks That

A male stickleback fish will attack other male sticklebacks that invade its nesting territory. It will only attack male fish, which display the red belly characteristic of the species. Which of the following is an ultimate causation of this behavior?

A) The eyes and brain of male sticklebacks are extra sensitive to the color red, leading to the automatic attack of red invaders.
B) The CNS reaction to the color red is a fixed sequence of unlearned acts directly linked to the red invaders.
C) Having a territory increases the chances of attracting a mate and passing along more genes to the next generation.
D) The sight of red stimulates the autonomic nervous system of male sticklebacks, generating an aggressive physiological response to fight.