Feng Is Thinking of Mowing Lawns Over the Summer

Multiple Choice

Feng is thinking of mowing lawns over the summer.His friend Jason mows lawns,and he says that the marginal cost of mowing the fourth lawn in a day is $40.Feng thinks about it and realizes that the total cost of mowing four lawns is:

A) $160.
B) $40.
C) $80.
D) not possible to determine from the information provided.