The Cyber Kill Chain is a framework that describes the stages of a cyberattack from reconnaissance to actions on objectives. The exploitation stage is where attackers take advantage of the vulnerabilities they have discovered in previous stages to further infiltrate a target's network and achieve their objectives. In this case, the malicious actor has gained access to an internal network by means of social engineering and does not want to lose access in order to continue the attack. This indicates that the actor is in the exploitation stage of the Cyber Kill Chain. Official References:
https://www.lockheedmartin.com/en-us/capabilities/cyber/cyber-kill-chain.html

Explanation
The incident response policy or plan is a document that defines the roles and responsibilities, procedures and processes, communication and escalation protocols, and reporting and documentation requirements for handling security incidents. The lead should review what is documented in the incident response policy or plan to determine who should be communicated with and when during a security incident, as well as what information should be shared and how. The incident response policy or plan should also be aligned with the organizational policies and legal obligations regarding incident notification and disclosure.

偵察はサイバー キル チェーンの最初の段階で、侵入テストを実行する前に潜在的なターゲットを調査することになります。偵察段階では、潜在的なターゲットの特定、その脆弱性の発見、そのターゲットと関係のある第三者の発見 (およびアクセスできるデータ)、既存のエントリ ポイントの調査、および新しいエントリ ポイントの発見などが含まれます。偵察はオンラインでもオフラインでも実行できます。この場合、アナリストは、外部に面した資産全体でネットワーク スキャンと脆弱性スキャンを実行するために、会社のネットワーク外の IP アドレスが使用されていることを発見します。これは、アナリストが攻撃者による偵察活動を目撃していることを示しています。公式リファレンス: https://www.lockheedmartin.com/en-us/capabilities/cyber/cyber-kill-chain.html

A security analyst's concern is that any discovered vulnerabilities in the OS that is approaching the end-of-life date will not be remediated by the vendor, leaving the system exposed to potential attacks. The other options are not directly related to the security analyst's role or responsibility. Verified Reference: CompTIA Cybersecurity Analyst (CySA+) Certification Exam Objectives, page 9, section 2.21

The best option to safeguard PII during an incident is to ensure permissions are limited in the investigation team and encrypt the data. This is because limiting permissions reduces the risk of unauthorized access or leakage of sensitive data, and encryption protects the data from being read or modified by anyone who does not have the decryption key. Option A is not correct because closing the data may hinder the investigation process and prevent collaboration with other parties who may need access to the data. Option C is not correct because deleting data that is no longer needed may violate legal or regulatory requirements for data retention, and may also destroy potential evidence for the incident. Option D is not correct because opening permissions to the company may expose the data to more people than necessary, increasing the risk of compromise or misuse.
References: CompTIA CySA+ Study Guide: Exam CS0-002, 2nd Edition, Chapter 4, "Data Protection and Privacy Practices", page 195; CompTIA CySA+ Certification Exam Objectives Version 4.0, Domain 4.0
"Compliance and Assessment", Objective 4.1 "Given a scenario, analyze data as part of a security incident", Sub-objective "Data encryption", page 23 CompTIA CySA+ Study Guide: Exam CS0-002, 2nd Edition : CompTIA CySA+ Certification Exam Objectives Version 4.0.pdf)