A firm’s production function is q = 12 x0.50 y 0.50, where x and y are the amounts of factors x and y that the firm uses as inputs. If the firm is minimizing unit costs and if the price of factor x is 5 times the price of factor y, the ratio in which the firm will use factors x and y is closest to:

a. x/y = 0.20.

b. x/y = 0.40.

c. x/y = 1.

d. x/y = 1.67.

e. x/y = 5.