At the End of 2012, Murray State Lenders Had a Balance

At the end of 2012, Murray State Lenders had a balance in its Allowance for Uncollectible Accounts of $4,500 (debit) before any adjustment. The company estimated its future uncollectible accounts to be $12,000 using the percentage-of-receivables method. Murray State's adjustment on December 31, 2012, to record its estimated uncollectible accounts included a:

A) Credit to Allowance for Uncollectible Accounts of $12,000.
B) Debit to Bad Debt Expense of $16,500.
C) Credit to Allowance for Uncollectible Accounts of $16,500.
D) Both b and c.