Final answer:
The control that can be used to ensure that all of the characters of a social security number are entered by a data entry clerk is data validation.
Step-by-step explanation:
The control that can be used to ensure that all of the characters of a social security number are entered by a data entry clerk is data validation. Data validation is a process that checks the accuracy and consistency of data being entered into a computer system. In the case of a social security number, a data validation rule can be set to ensure that the number is entered in the correct format, with the right number of digits and the proper placement of hyphens.