Why the answer debt is "account receivalbe" and credit is sales revenue? (Please type the asnwer for me)

Bills Catering Company is at its accounting year-end, December 31, 2017. The following data that must be considered were developed from the companys records and related documents. Give the adjusting entry required for each transaction at December 31, 2017.

a. On December 31, 2017, the company catered an evening gala for a local celebrity. The $7,500 bill was payable by the end of January 2018. No cash has been collected, and no journal entry has been made for this transaction.