The Opponent Process Theory of Color Vision Is Based on _________,And

The opponent process theory of color vision is based on _________,and best explains the processing of color at the level of the _________.

A) the existence of three types of cones;retina
B) the existence of three types of cones;primary visual cortex
C) antagonistic center-surround receptive fields;retina
D) antagonistic center-surround receptive fields;primary visual cortex