A profit maximizing firm that has labor as the only variable factor of production has a demand curve that is

a. equal to the marginal product of labor
b. equal to the marginal revenue product of labor
c. equal to the average product of labor
d. equal to the marginal cost of production

B)  Equal to the marginal revenue product of labor

Explanation:

A profit maximizing firm looks out basically for  the additional revenue that will be generated by increasing product sales by one unit.That is to say for every labor put into production an expected return revenues are been incured on them.

Option B -- equal to the marginal revenue product of labor

Explanation: it should be noted that, when one firm uses only one variable factor of production, that factor's marginal revenue product curve is the firm demand curve. Therefore, other options, which are "equal to the marginal product of labor", "equal to the average product of labor" and "equal to the marginal cost of production" are wrong

a is the correct answer, tell me if im right