Brawndo manufactures jumbo-sized energy drinks (sold by the gallon) and ships them direct to customers using United Parcel Service (UPS) at a flat rate per gallon. Which two terms below describe the cost of shipping their energy drinks?

a) Mixed cost and product cost

b) Fixed cost and period cost

c) Variable cost and period cost

d) Mixed and period cost

e) Variable cost and product cost

f) Fixed cost and product cost