With Respect to the Write-Off of an Uncollectible Account Receivable

With respect to the write-off of an uncollectible account receivable against the Allowance for Bad Debts account, a sound system of internal control would require:

A) the write-off be approved by two employees.
B) an investigation of why credit was extended to this customer in the first place.
C) a lawsuit to be initiated to recover the uncollectible amount.
D) the write-off to be made within six months after the date of sale.