Platys and Swordtails Are Related Tropical Freshwater Fish

Platys and swordtails are related tropical freshwater fish. In studies, researchers have shown that female platys prefer males with swords, even though males of their own species do not have them. What does this suggest about the origin of the swordtail feature?

A) Female preference for swords may have predated the origin of the feature itself.
B) Evolution of swords later led to evolution of female preference for swords.
C) The same gene that causes sword development also causes development of neural circuits for female preference.
D) Adjacent genes on the same chromosome cause sword development and development of neural circuits for female preference.