Tom's Landscaping Service Has Only One Variable Input,which Is Labor

Multiple Choice

Tom's Landscaping Service has only one variable input,which is labor.Tom's Landscaping Service's labor costs are $300 a day and Tom's Landscaping Service works on 9 yards per day.To work on 10 yards per day,Tom's Landscaping Service's labor costs increase to $325 a day.The marginal cost of working on the 10th yard is

A) $25.00.
B) $32.50.
C) $45.00.
D) indeterminate from the information given.