To avoid requiring tertiary functionality, backup functionality is not required during planned outages of the primary or backup functionality of _____ or less, or unplanned outages of the primary or backup functionality.

• A. 2 days
• B. 2 months
• C. 1 week
• D. 2 weeks

Answer: (D)

The question tests the time window during which only primary and backup functionality are expected to be enough, without needing a tertiary layer. The rule is that backup functionality is not required to provide tertiary coverage during planned outages of the primary or backup, and during unplanned outages of the primary or backup, for two weeks or less. In other words, if the outage (planned or unplanned) lasts up to two weeks, operations can continue relying on the existing two levels of capability without invoking a third (tertiary) level.

Two weeks is chosen as the threshold because it gives a practical window to restore full functionality while avoiding the need to maintain an additional, more expensive layer of redundancy for shorter disruptions. If the outage extends beyond two weeks, tertiary functionality would then be required to maintain reliability.

Why the other options don’t fit: two days or one week would impose a stricter redundancy requirement, requiring tertiary coverage sooner. Two months would delay the need for tertiary too long and could compromise reliability during longer outages.