Comprehensive and Detailed Step-by-Step Explanation:
Recovering from ransomware requires backups that are unaffected by the ransomware attack. Here's why offline backups are most effective:
A). Online backup: These are connected to the network and may also be compromised during an attack.
B). Incremental backup: While efficient, incremental backups rely on previous backups and are typically stored online, making them vulnerable to ransomware.
C). Differential backup: Similar to incremental backups, these are not immune if stored online or on compromised systems.
D). Offline backup: This is the BEST choice as offline backups are stored in a location that is not connected to the network, preventing ransomware from encrypting them.
Reference: CISM Job Practice Area 4 (Information Security Incident Management) includes guidance on establishing robust backup strategies for recovery.

A business continuity plan (BCP) is the best option that enables an organization to operate smoothly with reduced capacities when service has been disrupted, as it defines the processes and procedures to maintain or resume critical business functions and minimize the impact of the disruption on the organization's objectives, customers, and stakeholders. A BCP also includes strategies for resource management, communication, recovery, and testing.
References = CISM Review Manual 2022, page 3101; CISM Exam Content Outline, Domain 4, Knowledge Statement 4.82; CISM 2020: Business Continuity3; Part Two: Business Continuity and Disaster Recovery Plans4

The primary objective of a business impact analysis (BIA) is to determine recovery priorities. The BIA is used to identify and analyze the potential effects of an incident on the organization, including the financial impact, operational impact, and reputational impact. The BIA also helps to identify critical resources and processes, determine recovery objectives and strategies, and develop recovery plans. Reference: Certified Information Security Manager (CISM) Study Manual, Chapter 4, Business Impact Analysis.