Creating user accounts that automatically expire by a predetermined date is an effective control for granting temporary access to vendors and external support personnel.

Explanation/Reference:
Explanation:
Neural networks are effective in detecting fraud because they have the capability to consider a large number of variables when trying to resolve a problem.

Performing user acceptance testing (UAT) is the most important activity before implementing a new system, as it ensures that the system meets the user requirements and expectations, and that it is free of major defects. Documenting last-minute enhancements, performing a pre-implementation audit, and ensuring that code has been reviewed are also important activities, but they are not as critical as UAT. References: CISA Review Manual (Digital Version), Chapter 4, Section 4.2.2