According to the profession's Rules of Conduct, an auditor would be considered independent in which of the following instances?

a. The auditor's checking account is held at a client financial institution.

b. The auditor, an attorney, serves as the client's general counsel.

c. An employee of the auditor serves as the unpaid treasurer of a charitable organization that is an audit client.

d. The client owes the auditor fees for two consecutive years.

Choose the correct answer.