Payment by check is an important internal control over cash payments because A. the check must be signed by an authorized official. B. before signing the check, the official reviews the invoice supporting the payment. C. Both a and b D. None of the above

The correct answer is the option C: Both a and b.

Explanation:

To begin with, it is necessary to understand that in a business, transactions occur every day and therefore that the company's owner or its stuff must configurate a way to mantain control over the operations that happen daily and by doing that they ensure the fact of not having problems later with the law and plus they work better. Moreover, by paying with a check, this last one must be signed by an authorized official who previously  reviews it to know that every thing is in order and in that way avoid falsifications or the exit of cash that do not belong to a right expenditure.