Refer to the Following

Multiple Choice

refer to the following:
The price of capital (r) is $20.
-At the optimal combination of inputs for producing 14,000 units of output, what is the marginal rate of technical substitution (-) K/) L) ?

A) 2.5
B) 0.67
C) 1.5
D) 0.80
E) impossible to tell from the graph