Suppose the short run cost function can be written as TC=250 + 10Q. Average fixed cost equals

The correct answer is C. 10.

Average fixed cost (AFC) is the total fixed cost divided by the quantity produced. In this case, the total fixed cost is $250, so the average fixed cost is $250/Q = 10.

Option A is incorrect because it is the average variable cost. Option B is incorrect because it is the total cost. Option D is incorrect because it is the sum of the average fixed cost and the average variable cost.