An organization's backup policy states: 'Maintain three copies of data on two different media types, with one copy stored offsite.' This is known as:
Correct. This matches the description.
Why this answer
The 3-2-1 rule is a foundational data backup strategy that mandates maintaining three total copies of data, stored on two different types of media (e.g., disk and tape), with one copy located offsite to protect against site-level disasters. This directly matches the policy described, making option C correct.
Exam trap
The trap here is that candidates confuse the 3-2-1 rule with backup rotation schemes like GFS or incremental strategies, because all involve 'backup' and 'copies,' but only the 3-2-1 rule explicitly defines the count, media diversity, and offsite requirement.
How to eliminate wrong answers
Option A is wrong because an incremental backup strategy refers to a backup method that only copies data changed since the last full or incremental backup, not a rule about the number of copies, media diversity, or offsite storage. Option B is wrong because the grandfather-father-son (GFS) rotation is a tape rotation scheme that manages backup retention cycles (daily, weekly, monthly), not a specification for three copies on two media types with one offsite. Option D is wrong because a disaster recovery plan (DRP) is a comprehensive document outlining procedures for recovering IT infrastructure after a disaster, not a specific backup copy and media rule.