Final answer:
Each 1/4 cup serving of the cereal contains 12 grams of protein.
Step-by-step explanation:
A serving of breakfast cereal contains 3g of protein. To find out how many grams of protein are in each 1/4 cup serving, we can set up a proportion. Let x represent the number of grams of protein in each 1/4 cup serving:
3g / x = 1/4 cup / 1 serving
Cross-multiplying, we get:
x = (3g)(1 serving) / (1/4 cup)
Simplifying the expression on the right side of the equation gives us x = (3g)(4/1) = 12g
Therefore, each 1/4 cup serving of cereal has 12 grams of protein, which is not one of the given answer options.