The pattern of firing of receptor activity in response to red would be _____.

a. large firing from the S receptor, medium firing from the M receptor, and little firing from the L receptor large firing from the S receptor,

b. large firing from the M receptor, and little firing from the L receptor little firing from the S receptor,

c. a moderate firing from the M receptor, and large firing from the L receptor large firing from the S receptor,

d. large firing from the M receptor, and large firing from the L receptor