Which of the Following Is True of Retinal Color Opponent

Which of the following is true of retinal color opponent cells?

A) opponent cells are important detectors of color contrast
B) if blue-yellow opponent cells are excited by S-cones, they are inhibited by M-cones
C) if blue-yellow opponent cells are excited by S-cones, they are inhibited by L-cones
D) if red-green color opponent cells are excited by M-cone activation, they are inhibited by L-cone activation