Table 8-3 Julie Plans to Start a Pet-Sitting Service. She

Table 8-3
Julie plans to start a pet-sitting service. She surveyed her neighbourhood to determine the demand for this service. Assume that each person surveyed demands only one hour of pet sitting services per period. Table 8-3 above shows a portion of her survey results.
-Refer to Table 8-3.Suppose Julie's marginal cost of providing this service is constant at $7 and she charges $7 per hour.What is her marginal revenue?

A) It is $7 for the first hour and starts declining thereafter.
B) It is $7 for the first hour and starts increasing thereafter.
C) It is constant at $7.
D) It coincides with the figures in the table; $12 for the first hour, $10 for the second, $9 for the third and $8 for the fourth.