Continuous auditing is a method of performing audit-related activities on a real-time or near real-time basis.
Continuous auditing is best suited for real-time transactions, such as online banking, e-commerce, or electronic funds transfer, that require immediate verification and assurance. Low-value transactions are not necessarily suitable for continuous auditing, as they may not pose significant risks or require frequent monitoring. Irregular transactions are not suitable for continuous auditing, as they may not occur frequently or consistently enough to justify the use of continuous auditing techniques. Manual transactions are not suitable for continuous auditing, as they may not be captured or processed by automated systems that enable continuous auditing. References:
CISA Review Manual, 27th Edition, pages 307-3081
CISA Review Questions, Answers and Explanations Database, Question ID: 253

A key performance indicator (KPI) is a quantifiable measure of performance over time for a specific objective1. KPIs help organizations and teams track their progress and achievements towards their strategic goals. To be useful, a KPI must have a target value, which is the desired level of performance or outcome that the organization or team aims to achieve. A target value provides a clear direction and a benchmark for measuring success or failure. Without a target value, a KPI is meaningless, as it does not indicate whether the performance is good or bad, or how far or close the organization or team is from reaching their objective.

When auditing the alignment of IT to the business strategy, it is most important for the IS auditor to evaluate deliverables of new IT initiatives against planned business services. This can help the IS auditor to assess whether the IT initiatives are meeting the business needs and expectations, delivering value and benefits, and supporting the business objectives and goals. Comparing the organization's strategic plan against industry best practice is a possible technique for auditing the alignment of IT to the business strategy, but it is not the most important thing for the IS auditor to do, as industry best practice may not be applicable or relevant to the specific context or situation of the organization. Interviewing senior managers for their opinion of the IT function is a possible technique for auditing the alignment of IT to the business strategy, but it is not the most important thing for the IS auditor to do, as senior managers' opinions may be subjective or biased, and may not reflect the actual performance or outcomes of the IT function. Ensuring an IT steering committee is appointed to monitor new IT projects is a possible control for ensuring the alignment of IT to the business strategy, but it is not the most important thing for the IS auditor to do, as an IT steering committee may not be effective or efficient in monitoring new IT projects, and may not have sufficient authority or influence over the IT function.

A post-implementation review (PIR) is an assessment conducted at the end of a project cycle to determine if the project was indeed successful and to identify any existing flaws in the project1. One of the main objectives of a PIR is to evaluate the outcome and functional value of a project1. Therefore, an IS auditor should be most concerned with whether the system meets the intended requirements and delivers the expected benefits to the stakeholders. A system that does not have a maintenance plan is a major risk, as it may not be able to cope with changing needs, fix errors, or prevent security breaches. A maintenance plan is essential for ensuring the system's reliability, availability, and performance in the long term2.
The other options are less critical for a PIR, as they are more related to the project management aspects than the system quality aspects. The system may contain several minor defects that do not affect its functionality or usability, and these can be resolved in future updates. The system deployment may be delayed by three weeks due to unforeseen circumstances or dependencies, but this does not necessarily mean that the system is faulty or ineffective. The system may be over budget by 15% due to various factors such as scope creep, resource constraints, or market fluctuations, but this does not imply that the system is not valuable or beneficial.
References: 1: Post-Implementation Review Best Practices - MetaPM 2: What is Post-Implementation Review in Project Management?