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.