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 (credit) 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 $7,500.
C) Credit to Allowance for Uncollectible Accounts of $7,500.
D) Both b and c.