Trevor asks the restaurant for the recipe for the "Boa Brownie Bites" to ensure that he is not allergic to any of its ingredients. The recipe uses 15 cups of flour for every 5 cups of sugar.
Which of the following describes a unit rate for the recipe?

The recipe needs 3 cups of flour for each cup of sugar.
The recipe needs 3 cups of sugar for each cup of flour.
The recipe needs 12 cups of sugar for each cup of flour.
The recipe needs 12 cups of flour for each cup of sugar.