The primary objective of the information security incident response process is to minimize the negative impact to critical operations. An information security incident is an event that threatens or compromises the confidentiality, integrity, or availability of the organization's information assets or processes. The information security incident response process is a process that defines the roles, responsibilities, procedures, and tools for detecting, analyzing, containing, eradicating, recovering, and learning from information security incidents.
The main goal of the information security incident response process is to restore the normal operations as quickly and effectively as possible, and to prevent or reduce the harm or loss caused by the incident to the organization, its stakeholders, or its environment.
Conducting incident triage (A) is an important activity of the information security incident response process, but not the primary objective. Incident triage is the process of prioritizing and assigning the incidents based on their severity, urgency, and impact. Incident triage helps to allocate the appropriate resources, personnel, and time to handle the incidents, and to escalate the incidents to the relevant authorities or parties if needed.
However, incident triage is not the ultimate goal of the information security incident response process, but a means to achieve it.
Communicating with internal and external parties (B) is also an important activity of the information security incident response process, but not the primary objective. Communicating with internal and external parties is the process of informing and updating the stakeholders, such as management, employees, customers, partners, regulators, or media, about the incident status, actions, and outcomes. Communicating with internal and external parties helps to maintain the trust, confidence, and reputation of the organization, and to comply with the legal and contractual obligations, such as notification or reporting requirements. However, communicating with internal and external parties is not the ultimate goal of the information security incident response process, but a means to achieve it.
Classifying incidents (D) is also an important activity of the information security incident response process, but not the primary objective. Classifying incidents is the process of categorizing and labeling the incidents based on their type, source, cause, or impact. Classifying incidents helps to identify and understand the nature and scope of the incidents, and to apply the appropriate response procedures and controls. However, classifying incidents is not the ultimate goal of the information security incident response process, but a means to achieve it.
References = CISM Review Manual, 16th Edition, Chapter 4: Information Security Incident Management, Section: Incident Response Plan, page 1811

Phishing awareness training is the best way to mitigate the risk of employees clicking on malicious links in emails, as it educates them on how to recognize and avoid phishing attempts. (From CISM Review Manual
15th Edition)
References: CISM Review Manual 15th Edition, page 179, section 4.3.2.2.

Managed security solutions are services provided by external vendors that offer security expertise, resources, and tools to help organizations protect their information assets and systems. A primary benefit of managed security solutions is that they allow organizations to focus on their core business operations, while delegating the security tasks to the service provider. This can improve the efficiency and effectiveness of the organization, as well as reduce the complexity and cost of managing security internally. Managed security solutions can also provide a wider range of capabilities, easier implementation across an organization, and lower cost of operations, but these are not the primary benefits, as they may vary depending on the quality and scope of the service provider. References = CISM Review Manual, 16th Edition, ISACA, 2020, p. 841; CISM Online Review Course, Domain 3: Information Security Program Development and Management, Module 3:
Information Security Program Management, ISACA2