A competitive firm has a long- run total cost function c(y) = 3y 2 + 675 for y > 0 and c(0) = 0. Its long- run supply function is described as

a. y = p/6 if p > 90, y = 0 if p < 90. 4

b. y = p/3 if p > 88, y = 0 if p < 88.

c. y = p/3 if p > 93, y = 0 if p < 99.

d. y = p/6 if p > 93, y = 0 if p < 93.

e. y = p/3 if p > 95, y = 0 if p < 85.