A Competitive Firm Has a Long-Run Total Cost Function C(y)

A competitive firm has a long-run total cost function c(y) = 3y2 + 675 for y > 0 and c(0) = 0. Its long-run supply function is described as

A) y =if p > 90, y = 0 if p < 90.
B) y =if p > 88, y = 0 if p < 88.
C) y =if p > 93, y = 0 if p < 99.
D) y =if p > 93, y = 0 if p < 93.
E) y =if p > 95, y = 0 if p < 85.