On December 31,2011,the Balance in Pinnacle Exploration Company's Unearned Revenue

On December 31,2011,the balance in Pinnacle Exploration Company's Unearned revenue account is credit of $4,200.In January,2012,the company received an advance payment of $12,000 from a new customer for services to be performed.By January 31,adjustments had been made to recognize $8,500 of the revenue which had been earned during January.What would be the balance in Unearned revenue on January 31,2012?
A) $16,200 credit
B) $8,500 debit
C) $3,500 credit
D) $7,700 credit