Vote-on-account means the statutory acceptance of expenditure related to demands of grants till the passage of planning bill. This allows the government to obtain parliamentary approval for spending in the interim period before the full budget is passed. It enables the government to meet the necessary expenses and carry out essential functions without delay.

Option 1, the statutory acceptance of a planning bill, is not the correct definition of vote-on-account. Planning bills are separate from the interim budget.

Option 2, the statutory acceptance of a money bill, is also not the correct definition. Money bills relate to specific financial matters and are not directly related to the interim budget.

Option 3, the statutory acceptance of a report of account checking and documents produced by CAG, is not directly related to vote-on-account. CAG reports are separate from the interim budget process.

Therefore, the correct answer is option 4.