Dyanna Craig operates Concord Riding Academy. The academy's primary sources of revenue are riding fees and lesson fees, which are paid on a cash basis. Dyanna also boards horses for owners, who are billed monthly for boarding fees. In a few cases, boarders pay in advance of expected use. For its revenue transactions, the academy maintains the following accounts: Cash, Accounts Receivable, and Service Revenue. The academy owns 10 horses, a stable, a riding corral, riding equipment, and office equipment. These assets are accounted for in these accounts: Horses, Buildings, and Equipment. The academy also maintains the following accounts: Supplies, Prepaid Insurance, Accounts Payable, Salaries and Wages Expense, Advertising Expense, Utilities Expense, and Maintenance and Repairs Expense. Dyanna pays periodic cash dividends to stockholders. To record stockholders' equity in the business and dividends, three accounts are maintained: Common Stock, Retained Earnings, and Dividends. During the first month of operations, an inexperienced bookkeeper was employed. Dyanna Craig asks you to review the following eight entries of the 50 entries made during the month. In each case, the explanation for the entry is correct.