The primary purpose of an Incident Response (IR) plan is to provide a systematic, well-defined, and organized approach for handling security incidents. This structured process ensures that an organization can effectively identify, analyze, contain, eradicate, and recover from a security breach or attack. The plan outlines roles, responsibilities, and communication strategies to minimize operational impact, reduce recovery time and costs, and manage the incident in a consistent and predictable manner. It serves as a roadmap for security personnel to follow during the high-stress environment of an active incident, preventing ad-hoc and potentially counterproductive actions.

A. Logging and storing incident data is a critical component of incident analysis and post-incident activity, but it is not the plan's primary purpose, which is the active response itself.

C. An IR plan is often a requirement for compliance and certifications, but its fundamental purpose is operational security response, not simply fulfilling a documentation mandate.

D. This describes the function of an automated security tool like an Intrusion Prevention System (IPS), not the purpose of a procedural plan that guides human actions during an incident.

1. National Institute of Standards and Technology (NIST). (August 2012). Special Publication (SP) 800-61 Rev. 2, Computer Security Incident Handling Guide. Section 2.3.1, "Incident Response Plan," states that the plan provides "the roadmap for implementing the incident response capability" and should contain "the necessary information for the incident response team to perform its duties." The guide's entire structure is built around the incident response life cycle: preparation; detection and analysis; containment, eradication, and recovery; and post-incident activity.

(Available at: https://doi.org/10.6028/NIST.SP.800-61r2)

2. Carnegie Mellon University, Software Engineering Institute (SEI). (October 2004). Defining Incident Management Processes. CERT-RMM: A Capability Maturity Model for Managing Operational Resilience. Section: "Incident Management Process Area," page 119. This document describes the specific goals of incident management, which include preparing for, protecting from, detecting, responding to, and recovering from incidents, reinforcing the concept of a structured process.

3. University of California, Berkeley. Information Security Office, Incident Response Plan. The document's "Purpose" section states its goal is to "provide a framework for responding to information security incidents... to protect the confidentiality, integrity, and availability of its information assets." This aligns with defining a structured process for mitigation and recovery.

(Available via Berkeley's Information Security Office public documentation).