Which of the following is not true about accounting for long-term construction contracts? a. long-term construction contracts could show a contract asset or contract liability, depending on the relation between construction in progress and billings. b. billings on contracts in progress is a contra account to accounts receivable. c. gross profit is debited to construction in progress. d. when a customer is billed for payment due, billings on contracts in progress is credited at the same time accounts receivable is debited.