Figure 13-2 the Figure Below Depicts a Total Cost Function for a for a Firm

Figure 13-2
The figure below depicts a total cost function for a firm that produces cookies.

-Refer to Figure 13-2.Which of the following statements best captures the nature of the underlying production function?

A) Output increases at a decreasing rate with additional units of input.
B) Output increases at an increasing rate with additional units of input.
C) Output decreases at a decreasing rate with additional units of input.
D) Output decreases at an increasing rate with additional units of input.