Answer
(C)
Work Step by Step
The point on the graph for x=50 is approximately (50,3000)
which eliminates A and B. (Cost of 50 items =$\$ 3000$)
The slope of the tangent at x=50, $C^{\prime}(50)$ is not close to being horizontal ( 0 per item ),
as suggested by choice D ($\$ 0.50$ per item), so we estimate that our best choice is (C)
