If Franco's Pizza Parlor Knows That the Marginal Cost of the 500ᵗʰ

If Franco's Pizza Parlor knows that the marginal cost of the 500ᵗʰ pizza is $3.50 and that the average total cost of making 499 pizzas is $3.30,then

A) average costs are rising at Q = 500.
B) average costs are falling at Q = 500.
C) total costs are falling at Q = 500.
D) average variable costs must be falling.