If Px = Py, then when the consumer maximizes utility,

A) X must equal Y.
B) MU(X) must equal MU(Y) .
C) MU(X) may equal MU(Y) , but it is not necessarily so.
D) X and Y must be substitutes.

Marginal Utility

The extra pleasure or benefit gained by a consumer from using an additional unit of a product or service.

Utility Maximization

Utility maximization is a principle in economics that suggests consumers aim to get the greatest satisfaction possible from their disposable income, choosing the mix of goods and services that maximizes their utility.

Px

Often used as a notation for the price of a good x in economic models.