Three hundred firms supply the market for paint. For fifty of the firm

Three hundred firms supply the market for paint. For fifty of the firms, their short-run average variable costs are minimized at $10 and short-run total costs are minimized at $15.

For the remaining firms, the short-run average variable costs and short-run average total costs are minimized at $20 and $25, respectively. If each firm has a U-shaped marginal cost curve then the short-run market supply curve is A) U-shaped too
B) kinked at $10
C) kinked at $15
D) kinked at $20
E) kinked at $25

ANSWER

D