On-center cells: A. are excited by light that falls in the periphery of their receptive field. B. are excited by light that falls in the center of their receptive field. C. are inhibited by light that falls in the center of their receptive field. D. are excited by light that falls across their entire receptive field.

B) are excited by light that falls in the center of their receptive field.

Explanation:

There are two types of bipolar cells present in the retina which are differentiated on the way the centres of their receptive fields respond to light. The names of bipolar cells are ON-centre and OFF-centre.

If a light fall at the centre of the receptive field of a bipolar cell, it will experience an exciting effect on that cell, resulting in it being depolarized, it is an ON-center cell.

Hence, the correct option is B.