Tegan Walker Is About to Begin a Recurring Annual Audit

Tegan Walker is about to begin a recurring annual audit engagement. As the continuing auditor, her independence would ordinarily be considered to be impaired if the previous year's audit fee:

A) was only partially paid and the balance is being disputed.
B) has not been paid and will not be paid for at least twelve months.
C) has not been paid and the client has filed voluntary bankruptcy.
D) was settled by litigation.