The accounting manager at Essex Trucking Co. records the following transactions for March which have been journalized and posted to the proper accounts. Mar. 1 The business received $8,000 cash and issued common stock to stockholders. Mar, 2 Paid the first month's rent of $600. Mar. 3 Purchased equipment by paying $1,000 cash and executing a note payable for $4,000 Mar. 4 Purchased office supplies for $650 cash. Mar. 5 Billed a client for $13,000 of design services completed. Mar. 6 Received $7,000 on account for the services previously recorded. What is the ending balance in the Service Revenue account? $15.000 $7,000 $13,000 $8,000