Pauli's Pizza Offers One Slice for $2,two Slices for $3

Multiple Choice

Pauli's Pizza offers one slice for $2,two slices for $3.50,three slices for $4.50,and four slices for $5.00.The marginal cost of the third slice is:

A) $4.50.
B) $10.
C) $1.
D) $2.