Wolf Cola prepared an aging of its accounts receivable at December 31, 2010 and determined that the net realizable value of the receivables was $300,000. Additional information is available as follows:

Allowance for un-collectable accounts at 1/1/10 - credit balance: $34,000

Accounts written off as un-collectable during 2010: $23,000

Accounts receivable at 12/31/10: $325,000

Un-collectable accounts recovered during 2010: $5,000

For the year ended December 31, 2020, Wolf Cola's's un-collectable accounts expense would be:

a) $25,000

b) $23,000

c) $16,000

d) $9,000