Refer to the Image

Refer to the image.
The moonlit world depicted in the image appears to be drained of color because

A) we can only use two types of rod photoreceptors under these conditions.
B) in photopic conditions, only our rods are active.
C) in scotopic conditions, only our rods are active.
D) in photopic conditions, only our cones are active.
E) in scotopic conditions, only our S-cones are active.