51) If total costs are $50,000 when 1000 units are produced, and total costs are $50,100 when
1001 units are produced, we can conclude that
A) average variable costs are $100.
B) average total costs are $100.
C) average fixed costs are $100.
D) marginal costs are $100.
52) If average variable costs are increasing while average total costs are decreasing, then
A) marginal cost must lie between average variable and average total costs.
B) marginal cost must equal average variable cost.
C) marginal cost must equal average total cost.
D) fixed costs must be zero.
53) In a graph showing the short-run cost curves, the one curve which declines continuously as
we expand output is called
A) the average fixed cost curve.
B) the average variable cost curve.
C) the average total cost curve.
D) the marginal cost curve.