Using analytical tools to produce exception reports from the system and performance monitoring software is the most effective plan of action for a company that purchased and implemented system and performance monitoring software. Exception reports are reports that highlight deviations or anomalies from predefined thresholds or standards. Using analytical tools to produce exception reports can help to reduce the size and complexity of the system and performance monitoring reports, as well as to focus on the most relevant and critical information for review and action. The other options are less effective plans of action, as they may involve unnecessary costs, risks, or efforts. References:
* CISA Review Manual (Digital Version), Chapter 4, Section 4.2.21
* CISA Review Questions, Answers & Explanations Database, Question ID 219

A project business case is a document that describes the rationale and justification for initiating a project, based on its expected costs, benefits, risks, and feasibility. A project business case provides the most useful information to an IS auditor when selecting projects for inclusion in an IT audit plan, because it helps the IS auditor to:
* Understand the purpose, scope, objectives, and deliverables of the project
* Assess the alignment of the project with the organization's strategy, vision, and goals
* Evaluate the value proposition and return on investment of the project
* Identify the key stakeholders, sponsors, and owners of the project
* Analyze the potential risks and issues associated with the project
* Compare and prioritize the project with other competing projects
The other possible options are:
* A. Project charter: A project charter is a document that formally authorizes and defines the high-level scope, roles, responsibilities, and authority of a project. A project charter provides some useful information to an IS auditor when selecting projects for inclusion in an IT audit plan, but it is not the most useful information. A project charter does not provide enough details about the costs, benefits, risks, and feasibility of the project, which are essential for evaluating its suitability for an IT audit plan.
* B. Project plan: A project plan is a document that outlines the detailed scope, schedule, budget, resources, quality, and communication plans of a project. A project plan provides some useful information to an IS auditor when selecting projects for inclusion in an IT audit plan, but it is not the most useful information. A project plan does not provide enough information about the rationale, justification, value proposition, and alignment of the project with the organization's strategy and goals, which are important for assessing its relevance for an IT audit plan.
* C. Project issue log: A project issue log is a document that records and tracks the issues that arise during a project's execution and how they are resolved. A project issue log provides some useful information to an IS auditor when selecting projects for inclusion in an IT audit plan, but it is not the most useful information. A project issue log does not provide enough information about the purpose, objectives, benefits, and feasibility of the project, which are critical for determining its priority for an IT audit plan.

The most effective method to verify that a service vendor keeps control levels as required by the client is to conduct periodic on-site assessments using agreed-upon criteria. On-site assessments can provide direct evidence of whether the vendor's controls are operating effectively and consistently in accordance with the client's expectations and requirements. Agreed-upon criteria can ensure that the assessments are objective, relevant, and reliable. The other options are not as effective as on-site assessments in verifying the vendor's control levels. Periodically reviewing the SLA with the vendor can help monitor whether the vendor meets its contractual obligations and service standards, but it does not provide assurance of whether the vendor's controls are adequate or sufficient. Conducting an unannounced vulnerability assessment of vendor's IT systems can help identify any weaknesses or gaps in the vendor's security controls, but it may violate the terms and conditions of the vendor-client relationship or cause operational disruptions. Obtaining evidence of the vendor's CSA can provide some indication of whether the vendor's controls are self-monitored and reported, but it does not verify whether the vendor's controls are independent or accurate. References: CISA Review Manual (Digital Version), Chapter 5, Section 5.4