Tara Notices That Studying for One Hour After Class Increases

Multiple Choice

Tara notices that studying for one hour after class increases her economics grade by 11 points.The second hour yields a 7-point gain,the third hour yields a 4-point gain,and the fourth hour yields only a 1-point gain.This means that the marginal _____ of studying decreases with study hours.

A) cost
B) benefit
C) opportunity cost
D) time