Which of the following is true? a. A nonbusiness bad debt deduction can be taken any year after the debt becomes totally worthless. b. In determining whether a debt is a business or nonbusiness bad debt, the debtor's use of the borrowed funds is important. c. The amount of partial worthlessness on a nonbusiness bad debt is deducted in the year partial worthlessness is determined. The period in which an accrual basis taxpayer can deduct an expense is determined by applying the. d. All of the above. e. None of the above.