Access to the spreadsheet is given only to those who require access is the most important control for maintaining the security of data in the spreadsheet. An IS auditor should ensure that the principle of least privilege is applied to limit the access to sensitive financial data and prevent unauthorized disclosure, modification, or deletion. The other options are less important controls that may enhance the accuracy, availability, or integrity of data in the spreadsheet, but not its security. References:
* CISA Review Manual (Digital Version), Chapter 6, Section 6.31
* CISA Review Questions, Answers & Explanations Database, Question ID 210