Guinea Pigs R Us Magazine Company's Unearned Revenue Account Had

Guinea Pigs R Us magazine company's Unearned Revenue account had a balance of $25,400 on January 1, 2019. On December 31, 2019, as part of the adjusting entry, they recognized Subscription revenue of $29,600. The December 31, 2019 balance of the Unearned Revenue account was $24,600.
What must have been the amount of cash received by the Guinea Pigs R Us magazine company from customers during the year 2019?

A) $20,400
B) $28,800
C) $29,600
D) $30,400