Suppose the Marginal Physical Product of Labor at a Shoe

Multiple Choice

Suppose the marginal physical product of labor at a shoe string factory is 1,500 shoestrings per hour at 80 hours, 1,200 per hour shoestrings at 90 hours, 800 shoestrings per at 100 hours, and 300 shoestrings per hour at 110 hours.If a shoestring maker's wages are $60 per hour and each string sells for $0.05.What is the optimal use of labor for making shoestrings?

A) 80 hours
B) 90 hours
C) 100 hours
D) 110 hours