An auditor compares the current-year revenues and expenses with those of the prior year and investigates all changes exceeding 5 percent. By this procedure the auditor would be most likely to learn that

a. Fourth-quarter payroll taxes in the current year were not paid.

b. The client changed its capitalization policy for small tools in the cur- rent year.

c. A current-year increase in property tax rates has not been recognized in the client's accrual.

d. The current-year provision for uncollectible accounts is inadequate because of worsening economic conditions.