A is corrent. A validation check at data entry that verifies that a quantity field contains only numbers is an example of a programmatic means of ensuring the accuracy of the value in that no nonnumeric characters are permitted; this is an input control.
B is incorrect. A processing control ensures that data are complete and accurate during updating.
C is incorrect. The purpose of an audit trail control is to ensure that a chronological record of all relevant events in a system has been recorded.
D is incorrect. A data security control ensures that only authorized individuals are permitted to access and use a system.
| 
