Discovery sampling is an appropriate sampling method for an IS auditor who intends to launch an intensive investigation if one exception is found. Discovery sampling is a type of attribute sampling that determines the sample size based on an acceptable risk of not finding at least one occurrence of an attribute when a given rate of occurrence exists in a population. Discovery sampling can be used by an IS auditor who wants to detect fraud or errors that have a low probability but high impacton an audit objective. The other options are not appropriate sampling methods for this purpose, as they may involve judgmental sampling, variable sampling, or stratified sampling. References:
CISA Review Manual (Digital Version), Chapter 2, Section 2.31
CISA ReviewQuestions, Answers and Explanations Database, Question ID 230

An IS auditor is analyzing a sample of accounts payable transactions for a specific vendor and identifies one transaction with a value five times as high as the average transaction. The next step that the auditor should do is to request an explanation of the variance from the auditee. This is because the variance may indicate an error, fraud, or an unusual but legitimate transaction that requires further investigation. The auditor should not report the variance immediately to the audit committee without verifying its cause and significance. The auditor should not increase the sample size to 100% of the population without considering the cost-benefit analysis and the sampling methodology. The auditor should not exclude the transaction from the sample population without justification, as itmay affect the validity and reliability of the audit results. References: CISA Review Manual (Digital Version), [ISACA Auditing Standards]

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 auditor's primary concern when capacity management for a key system is being performed by IT with no input from the business would be an unanticipated increase in business's capacity needs. This could result in performance degradation, service disruption or customer dissatisfaction if IT is not able to provide sufficient capacity to meet the business demand. Failure to maximize the use of equipment, cost of excessive data center storage capacity or impact to future business project funding are secondary concerns that relate to resource optimization or budget allocation, but not to service delivery or customer satisfaction. References: ISACA, CISA Review Manual, 27th Edition, 2018, page 374

Deep packet inspection (DPI) is a core capability of data loss prevention (DLP) tools that allows the analysis of the content of data packets in transit. This helps detect the unauthorized movement of sensitive data by examining packet-level details.
Network Traffic Logs (Option A):These provide historical data but do not actively detect data in transit.
Data Inventory (Option C):Useful for identifying where sensitive data resides but not for monitoring its movement.
Proprietary Encryption (Option D):Protects data but does not detect unauthorized transmission.
Reference:ISACA CISA Review Manual, Job Practice Area 4: Protection of Information Assets.