Which Tier level is described by basic redundancy?

• A. Tier II
• B. Tier III
• C. Tier I
• D. Tier IV

Answer: (C)

Understanding how tier levels relate to redundancy helps here. Tier levels describe how much backup and fault tolerance a facility has. The simplest, baseline level provides only minimal protection against failures—just enough redundancy to cover basic needs but not enough to keep running through serious outages. That describes Tier I: the essential infrastructure with a single path for power and cooling and non-redundant components, meaning downtime can occur during maintenance or a component failure. As you move up the tiers, redundancy increases—Tier II adds more redundant components, Tier III enables concurrent maintenance with a single active path, and Tier IV delivers full fault tolerance with fully redundant, dual active paths. So basic redundancy aligns with the Tier I level.