Consumers Are Willing to Purchase a Product Up to the Point

Consumers are willing to purchase a product up to the point where

A) the marginal benefit of consuming the product is equal to the marginal cost of consuming it.
B) the consumer surplus is equal to the producer surplus.
C) the marginal benefit of consuming the product equals the area below the supply curve and above the market price.
D) the marginal benefit of consuming a product is equal to its price.