The correct answer is C because adding additional expansion chassis changes the physical hardware boundary of the HPE Superdome Flex complex and the resources assigned to the existing nPartition. Such a change cannot be treated like a live virtual-machine operation or a simple online software adjustment. The existing nPartition must be powered off before the physical expansion and partition-resource changes can be completed safely and consistently. Option A is incorrect because HPE OneView management does not require removing the nPartition from management merely to perform a hardware expansion; HPE OneView supports management of Superdome Flex-class infrastructure. Option B is incorrect because adding expansion chassis does not require replacing an expansion chassis with another base chassis for I/O redundancy in the way stated. Option D is also insufficient because placing the partition into a maintenance mode from the Rack Management Controller CLI is not equivalent to powering off the partition for a chassis-level expansion. The course includes Superdome Flex and scale-up compute designs for database and mission-critical workloads, so this question validates correct lifecycle planning for large HPE scale-up systems.