Figure 13-1 The Figure Below Depicts a Production Function for a Firm

Figure 13-1
The figure below depicts a production function for a firm that produces cookies.

-Refer to Figure 13-1.With regard to cookie production,the figure implies

A) diminishing marginal product of workers.
B) diminishing marginal cost of cookie production.
C) decreasing cost of cookie production.
D) increasing marginal product of workers.