The labour supply curve faced by a large firm in a small city is given by w = 60 + 0.05L, where L is the number of units of labor per week hired by the large firm and w is the weekly wage rate that it pays. If the firm is currently hiring 1,000 units of labor per week, then the marginal cost of a unit of labor to the firm

a) equals the wage rate.

b) is twice the wage rate.

c) equals the wage rate plus $100.

d) equals the wage rate plus $50.

e) equals the wage rate plus $150