Which of the following curves is not U shaped?

A. marginal cost curve
B. average fixed cost curve
C. average total cost curve
D. average variable cost

Correct Answer: Option B

B. average fixed cost curve

Explanation

The average fixed costs AFC curve is downward sloping because fixed costs are distributed over a larger volume when the quantity produced increases. AFC is equal to the vertical difference between ATC and AVC. Variable returns to scale explain why the other cost curves are U-shaped.