Gallons of Milk at a Local Grocery Store Are Priced

Multiple Choice

Gallons of milk at a local grocery store are priced at one for $4.00, or two for $6.00.The marginal cost of buying a second gallon of milk:

A) equals $6.00.
B) equals $4.00.
C) equals $3.00.
D) equals $2.00.
E) equals zero dollars.