loading balance and transaction data (option B) primarily focuses on transferring data into the new system but does not comprehensively test the system's processing capabilities, logic, or its ability to handle various transaction scenarios.

d is answer

The most assurance over the completeness and accuracy of loan application processing with respect to the implementation of a new system can be obtained by running historical transactions through the new system. Historical transactions are transactions that have been processed and recorded by the old system in the past. Running historical transactions through the new system can provide the most assurance over the completeness and accuracy of loan application processing, by comparing the results and outputs of the new system with those of the old system, and verifying whether they match or differ. This can help identify and resolve any errors or issues that may arise from the new system, such as data conversion, functionality, compatibility, etc. Comparing code between old and new systems is a possible way to obtain some assurance over the completeness and accuracy of loan application processing with respect to the implementation of a new system, but it is not the most effective one.

Reviewing quality assurance (QA) procedures is a possible way to obtain some assurance over the completeness and accuracy of loan application processing with respect to the implementation of a new system, but it is not the most effective one. QA procedures are steps or activities that ensure that a system meets its quality standards and requirements, such as testing, verification, validation, etc. Reviewing QA procedures can provide some assurance over the completeness and accuracy of loan application processing, by evaluating whether the new system has been properly tested and verified before implementation. However, this may not be adequate or accurate, as QA procedures may not cover all aspects or scenarios of loan application processing, and may not reveal any errors or issues that may arise after implementation.