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, bycomparing 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. Code is a set of instructions or commands that define how a system operates or functions. Comparing code between old and new systems can provide some assurance over the completeness and accuracy of loan application processing, by checking whether the logic, algorithms, or functions of the new system are consistent or equivalent with those of the old system. However, this may not be sufficient or reliable, as code may not reflect the actual performance or outcomes of the system, and may not detect any errors or issues that may occur at the data or user level. 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. Loading balance and transaction data to the new system 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. Balance and transaction data are data that reflect the status and history of loan applications in a system, such as amounts, dates, payments, etc. Loading balance and transaction data to the new system can provide some assurance over the completeness and accuracy of loan application processing, by transferring data from the old system to the new system and ensuring that they are consistent and correct. However, this may not be enough or valid, as balance and transaction data may not represent all aspects or features of loan application processing, and may not indicate any errors or issues that may arise