Nutanix documentation for Erasure Coding is explicit: a cluster must have a minimum of four nodes to enable erasure coding, and for RF2 the minimum remains four nodes. Nutanix further explains that RF3 with erasure coding requires six nodes, which helps distinguish the two thresholds clearly for exam purposes. Since the question asks specifically about Replication Factor 2 and Erasure Coding, the minimum supported node count is 4. ( Nutanix ) This question is testing one of the most common node-count rules in Nutanix storage efficiency. A three-node cluster can provide RF2 storage, but that does not automatically mean erasure coding is available there.
Erasure coding introduces its own resiliency and stripe-width requirements, and Nutanix sets the minimum at four nodes for RF2. The values 5 and 6 are distractors meant to confuse RF2 and RF3 rules. Because the official requirement is four nodes for RF2 EC, the correct answer is B. ( Nutanix )