On December 1, the Simpson marketing company received $7,500 from a customer for a 2 month marketing plan to be completed January 31st of the following year. The cash receipt was recorded as unearned fees. The adjusting entry for the year ended December 31st would include:

A. a credit to unearned fees for $2,500

B. a debit to unearned fees for $3,750

C. credit to unearned fees for $5,000

D. a debit to unearned fees for $7,500

E. a debit to earned fees for $5,000