Which statement best describes fault tolerance?

• A. High availability reduces downtime via redundancy.
• B. Fault tolerance continues operation even in failures without interruption.
• C. Fault-tolerant systems incur higher cost and complexity.
• D. High availability eliminates all failures.

Answer: (B)

Fault tolerance is the ability of a system to keep operating even when components fail, using redundant hardware and automatic failover so there is no noticeable interruption. That’s why the statement describing continuous operation during failures matches this concept best—no downtime when something goes wrong because the system seamlessly switches to redundant parts.

High availability aims to minimize downtime through redundancy and rapid failover, but it can involve a brief interruption during the transition. The notion that fault-tolerant systems are always cheaper or simpler isn’t accurate; they are typically more complex and costly due to the extra redundancy. And the idea that high availability eliminates all failures is not correct—no system can guarantee zero failures, though fault tolerance strives to maintain continuous operation despite faults.