Which of the Following Is Not True of the Marginal

Multiple Choice

Which of the following is not true of the marginal rate of substitution?

A) It is the rate at which we substitute good X for good Y in consumption.
B) It will be equal to the price ratio when the consumer maximises utility.
C) It is the ratio of the total utility of X to the total utility of Y.
D) It is the rate at which we substitute good X for good Y in production.
E) It is the ratio of the marginal utility of X to the marginal utility of Y.