The Following Data Show the Total Output for a Firm

Multiple Choice

The following data show the total output for a firm when different amounts of labour are combined with a fixed amount of capital.Assume that the wage per unit of labour is $10 and the cost of the capital is $50.
TABLE 7-3
-Refer to Table 7-3.If this firm is producing 20 units of output per period its marginal cost is

A) $1.00.
B) 50 cents.
C) $1.67.
D) 16.7 cents.
E) $10.00.