Here are the solutions to the questions: i. Which of the following errors affects the trial balance agreement? An error of single entry* occurs when only one side of a transaction is recorded, or an incorrect amount is entered on one side. This will cause the total debits and credits in the trial balance to be unequal. Errors of omission (complete), commission, and principle do not affect the agreement of the trial balance because they involve equal debits and credits, even if incorrect. The correct answer is C. ii. What is it called when a transaction is recorded in the wrong class of account. An error of principle* occurs when a transaction is recorded in the wrong type of account, violating accounting principles (e.g