Which Stimulus Would Optimally Activate an ON-Center Ganglion Cell

Multiple Choice

Which stimulus would optimally activate an ON-center ganglion cell?

A) A spot of light in the center of the receptive field
B) A shadow in the center of the receptive field
C) A ring of light covering the surround of the receptive field
D) A large spot of light covering both the center and surround portions of the receptive field
E) A large shadow covering both the center and surround portions of the receptive field