Which of the following describes the process through which bad debt expense is estimated under the balance sheet approach?

a.Estimate bad debt expense as percentage of each period's outstanding AR.

b.Estimate bad debt expense as a percentage of each period's net credit sales.

c.Subtract the beginning balance of the allowance account from the estimated NRV of AR.

d.Subtract the beginning balance of the allowance account from the difference between the estimated NRV of AR and ending balance of AR.