A legacy application is running on an operating system that is no longer supported by the vendor. If the organization continues to use the current application, which of the following should be the IS auditor`s GREATEST concern? 

Answer options:

A. Potential exploitation of zero-day vulnerabilities in the system
B. Inability to update the legacy application database
C. Increased cost of maintaining the system
D. Inability to use the operating system due to potential license issues

A