At Equilibrium,the Marginal Rate of Substitution Describes

Multiple Choice

At equilibrium,the marginal rate of substitution describes:

A) the slope of the budget constraint.
B) the number of units of one good that a consumer is willing to trade for an additional unit of another good, holding utility fixed.
C) the slope of the demand curve.
D) the number of units of one good that a consumer is willing to trade for an additional unit of another good in order to increase utility by 1 unit.
E) a and b