The answer is a, please explain why

3. Which of the following errors would cause the Balance Sheet and Statement of Owner's Equity columns of a work sheet to be out of balance? a. Entering a revenue amount in the Balance Sheet and Statement of Owner's Equity Debit column b. Entering a liability amount in the Balance Sheet and Statement of Owner's Equity Credit column. c. Entering an expense amount in the Balance Sheet and Statement of Owner's Equity Debit column d. Entering an asset amount in the Income Statement Debit column. e. Entering a liability amount in the Income Statement Credit column