The Table Below Shows How the Marginal Benefit of Videotape

The table below shows how the marginal benefit of videotape rentals varies for Carol with the number rented per month. The price of each tape rental is reduced from $2.99 to $1 .99.Assuming that the price of a rental accurately reflects the marginal cost to Carol and that she is rational, she will increase the number of tapes rented per month from:

A) one to two.
B) two to three.
C) three to four.
D) four to five.