A load balancer is a tool or application that distributes incoming network traffic among multiple servers in a server farm, so that no server is overwhelmed and the performance of the system is optimized1. A load balancer can help the agency to handle the large influx of traffic to a regional office by balancing the workload among the available servers and preventing service disruptions. A load balancer can also provide high availability and fault tolerance by rerouting traffic to online servers if a server becomes unavailable2.
A virtual firewall is a software-based firewall that protects a virtual network or environment from unauthorized access and malicious attacks. A virtualfirewall can enhance the security of the agency's network, but it does not improve the performance of its servers.
A proxy server is an intermediary server that acts as a gateway between the client and the destination server, hiding the client's IP address and providing caching and filtering functions. A proxy server can improve the security and privacy of the agency's network, but it does not improve the performance of its servers.
A virtual private network (VPN) is a secure connection between two or more devices over a public network, such as the internet. A VPN can encrypt and protect the data transmitted over the network, but it does not improve the performance of the agency's servers.

The greatest concern for an IS auditor when evaluating an organization's IT strategy and plans is that IT is not engaged in business strategic planning, as this indicates a lack of alignment between IT and business objectives, which could result in inefficient and ineffective use of IT resources and capabilities. The absence of a defined IT security policy, the nondistribution of business strategy meeting minutes, and the inadequate documentation of IT strategic planning are also issues that should be addressed by an IS auditor, but they are not as significant as IT's noninvolvement in business strategic planning. References: CISA Review Manual (Digital Version), Chapter 3, Section 3.1

Secure code reviews as part of a continuous deployment program are preventive controls. Preventive controls are controls that aim to prevent or avoid undesirable events or outcomes from occurring, such as errors, defects, or incidents. Secure code reviews are activities that examine and evaluate the source code of a software or application to identify and eliminate any vulnerabilities, flaws, or weaknesses that may compromise its security, functionality, or performance. Secure code reviews as part of a continuous deployment program can help prevent or avoid security issues or incidents from occurring by ensuring that the code is secure and compliant before it is deployed to production. The other options are not correct types of controls for secure code reviews as part of a continuous deployment program, as they have different meanings and functions. Detective controls are controls that aim to detect or discover undesirable events or outcomes that have occurred, such as errors, defects, or incidents. Logical controls are controls that use software or hardware mechanisms to regulate or restrict access to IT resources, such as data, systems, or networks.
Corrective controls are controls that aim to correct or rectify undesirable events or outcomes that have occurred, such as errors, defects, or incidents. References: CISA Review Manual (Digital Version), Chapter 3, Section 3.2

The system only allows payments to vendors who are included in the system's master vendor list is an example of a preventative control in an accounts payable system. A preventative control is a control that aims to prevent errors or irregularities from occurring in the first place. By restricting payments to vendors who are authorized and verified in the master vendor list, the system prevents unauthorized or fraudulent payments from being made. The other options are examples of other types of controls, such as backup (recovery), reconciliation (detective), and communication (directive) controls. References: CISA Review Manual, 27th Edition, page 223