Refer to the Following

Multiple Choice

Refer to the following:

A producer is hiring 20 units of labor and 6 units of capital (bundle A) . The price of labor is $10, the price of capital is $2, and at A, the marginal products of labor and capital are both equal to 20.

-Beginning at A, if the producer increases labor by one unit and decreases capital by 1 unit, then

A) cost remains constant and output increases by 20 units.
B) cost remains constant and output decreases by 20 units.
C) output remains constant and cost increases by $8.
D) output remains constant and cost decreases by $8.
E) both cost and output remain constant.