Kate is a professional opera singer who gives voice lessons. the vocal-music industry is competitive. kate
hires a business consultant to analyze her financial records. the consultant recommends that kate give
fewer voice lessons. the consultant must have concluded that kate's
a) total revenues exceed her total accounting costs.
b) marginal revenue exceeds her total cost.
c) marginal revenue exceeds her marginal cost.
d) marginal cost exceeds her marginal revenue.

D

Explanation:

The industry is a competitive market; hence Kate is told to give fewer lesson because her marginal cost (cost of producing an additional vocal music lesson)  is greater than the marginal revenue (additional revenue she receives).

\ rc) marginal income exceeds its marginal cost.

Explanation:

In microeconomics, marginal income is the change in total income that occurs when the quantity sold increases a unit, that is, the increase in total income that is the additional sale of a unit of a particular good.