Use the Following to Answer Question

Multiple Choice

Use the following to answer question:
-(Figure: Marginal Benefits and Marginal Costs) Use Figure: Marginal Benefits and Marginal Costs.More time spent studying economics adds points to economics scores (MB) but subtracts points from accounting scores (MC) .The marginal benefit of studying economics for two hours is _____ points,and the marginal cost is _____ points.

A) 40;0
B) 30;10
C) 20;20
D) 10;30