The Vertical Distance Between Average Total Cost and Average Variable

The vertical distance between average total cost and average variable cost curves decreases as output increases because

A) it is traditional to draw the curves that way.
B) marginal cost first falls and then rises.
C) in geometry, both curves must reach their minimums on the marginal cost curve.
D) marginal product first rises and then falls.
E) average fixed cost decreases as output increases.