The primary purpose of performing a parallel run of a new system is to validate the new system against its predecessor. A parallel run is a strategy for system changeover where a new system slowly assumes the roles of the older system while both systems operate simultaneously. This allows for comparison of the results and outputs of both systems to ensure that the new system is working correctly and reliably. A parallel run can also help identify and resolve any errors, discrepancies, or inconsistencies in the new system before the old system is discontinued.

The other options are not the primary purpose of performing a parallel run of a new system. A. To train the end users and supporting staff on the new system. Training is an important part of system implementation, but it is not the main reason for doing a parallel run. Training can be done before, during, or after the parallel run, depending on the needs and preferences of the organization. B. To verify the new system provides required business functionality. Verifying the business functionality of the new system is part of user acceptance testing (UAT), which is a formal and structured process of testing whether the new system meets the specifications and expectations of the users and stakeholders. UAT is usually done before the parallel run, as a prerequisite for system changeover. C. To reduce the need for additional testing. Reducing the need for additional testing is not the primary purpose of performing a parallel run, but rather a possible benefit or outcome of doing so. A parallel run can help ensure that the new system is thoroughly tested and validated in a real-worldenvironment, which may reduce the likelihood of encountering major issues or defects later on. However, additional testing may still be needed after the parallel run, depending on the feedback and evaluation of the users and stakeholders.