Which of the following items would most likely be a violation of the materiality constraint?

a. A company did not separately report an unusual gain of $50,000. Its income from operations was $5,000,000.

b. A company having reported total assets of $20,000,000 immediately expensed the purchase of 20 pencil sharpeners that have an estimated useful life of three years.

c. A $25,000 illegal bribe by an executive of the company to a foreign official was not separately disclosed in the annual report.

d. A $5,000 expenditure to improve a building that originally cost $5,000,000 was immediately expensed.