The Following Table Shows the Marginal Productivity of Different Units

The following table shows the marginal productivity of different units of labor for producing a product. Table 14.4
In the table,
MR: Marginal Revenue
MPP: Marginal Physical Product
In Table 14.4, if marginal revenue product is equal to the product of MPP and MR, what wage rate would be consistent with a profit-maximizing firm hiring six laborers?

A) $6
B) $10
C) $12
D) $18
E) $24