Because the Height of the Demand Curve Measures the Marginal

Because the height of the demand curve measures the marginal value of the good to consumers, the fact that a demand curve slopes downward to the right illustrates that

A) as more of a product is consumed, consumers will value additional units less.
B) as more of a product is consumed, consumers will value additional units more.
C) the value of additional units of the good is unrelated to the amount consumed.
D) the cost of production for a good generally rises as more of it is produced.