Explain why each of the following audits would be classified as (1) financial statement, (2) operational, or (3) compliance.

a. Audit of the contract costs of building jet fighter planes.

b. Audit by internal auditors of the efficiency of purchasing operations.

c. Audit by a CPA firm of whether a state government agency operated in accordance with its contract with the federal government.

d. Audit of a tax return by an Internal Revenue Service agent.

e. Audit of a company's financial statements by a CPA firm.