A router is a type of device that sits on the perimeter of a corporate or home network, where it obtains a public IP address and then generates private IP addresses internally. A router connects two or more networks and forwards packets between them based on routing rules. A router can also provide network address translation (NAT) functionality, which allows multiple devices to share a single public IP address and access the internet. A switch is a type of device that connects multiple devices within a network and forwards packets based on MAC addresses. An intrusion prevention system (IPS) is a type of device that monitors network traffic and blocks or modifies malicious packets based on predefined rules. A gateway is a type of device that acts as an interface between different networks or protocols, such as a modem or a firewall. References: CISA Review Manual (Digital Version), [ISACA Glossary of Terms]

The role within the RACI chart that would provide information on who has oversight of staff performing a specific task is accountable. A RACI chart is a matrix that defines and assigns the roles and responsibilities of different stakeholders for a project, process, or activity. RACI stands for responsible, accountable, consulted, and informed. Accountable is the role that has the authority and oversight to approve or reject the work done by the responsible role. The other options are not the roles that provide information on who has oversight of staff performing a specific task, as they have different meanings and functions. Consulted is the role that provides input or advice to the responsible or accountable roles. Informed is the role that receives updates or reports from the responsible or accountable roles. Responsible is the role that performs or executes the work or task. References: CISA Review Manual (Digital Version), Chapter 3, Section 3.3

The primary purpose of obtaining a baseline image during an operating system audit is to identify atypical running processes. A baseline image is a snapshot of the normal state and configuration of an operating system, including the processes that are expected to run on it. By comparing the current state of the operating system with the baseline image, an IS auditor can detect any deviations or anomalies that may indicate unauthorized or malicious activity, such as malware infection, privilege escalation, or data exfiltration. A baseline image can also help an IS auditor to assess the performance and efficiency of the operating system, as well as its compliance with security standards and policies.
Verifying antivirus definitions (option B) is not the primary purpose of obtaining a baseline image, although it may be a part of the baseline configuration. Antivirus definitions are the files that contain the signatures and rules for detecting and removing malware. An IS auditor may verify that the antivirus definitions are up to date and consistent across the operating system, but this does not require obtaining a baseline image.
Identifying local administrator account access (option C) is not the primary purpose of obtaining a baseline image, although it may be a part of the baseline configuration. Local administrator accounts are user accounts that have full control over the operating system and its resources. An IS auditor may identify and review the local administrator accounts to ensure that they are properly secured and authorized, but this does not require obtaining a baseline image.
Verifying the integrity of operating system backups (option D) is not the primary purpose of obtaining a baseline image, although it may be a part of the backup process. Operating system backups are copies of the operating system data and settings that can be used to restore the system in case of failure or disaster. An IS auditor may verify that the operating system backups are complete, accurate, and accessible, but this does not require obtaining a baseline image.
References: : Linux security and system hardening checklist : CISA Certification | Certified Information Systems Auditor | ISACA : CISA Certified Information Systems Auditor Study Guide, 4th Edition : CISA - Certified Information Systems Auditor Study Guide [Book]

Reconciliation of total amounts by project is the best control to ensure that data is accurately entered into the job-costing system from spreadsheets. Reconciliation is a process of comparing two sets of data to identify any differences or discrepancies between them. By reconciling the total amounts by project from spreadsheets with those from the job-costing system, any errors or omissions in data entry can be detected and corrected.
Validity checks are controls that verify that data conforms to predefined formats or ranges. They can prevent entry of character data into numeric fields, but they cannot ensure that the numeric data is correct or complete.
Reasonableness checks are controls that verify that data is within expected or acceptable limits. They can detect outliers or anomalies in data, but they cannot ensure that the data matches the source. Display back of project detail after entry is a control that allows the user to review and confirm the data entered into the system. It can help reduce human errors, but it cannot guarantee that the data is accurate or consistent with the source. References: Information Systems Operations and Business Resilience, CISA Review Manual (Digital Version)

Quality control reviews are the best way to demonstrate to senior management and the board that an audit function is compliant with standards and the code of ethics. These reviews assess the efficiency and effectiveness of the audit function, ensure compliance with audit standards and ethics, and identify areas for improvement12. While audit staff interviews, control self-assessments (CSAs), and corrective action plans can provide valuable insights, they do not offer the same level of assurance as a comprehensive quality control review12.
References: The Institute of Internal Auditors1, AuditBoard2