If an administrator deploys an NC2 cluster using an existing AWS network, in which type...

To deploy an NC2 cluster using an existing AWS network, the NAT Gateway should be placed in a public subnet. A public subnet is one that has a route to an Internet Gateway, allowing the NAT Gateway to provide outbound internet access for resources in private subnets. The NAT Gateway is used to enable instances in private subnets to access the internet while keeping them secure by not exposing them directly to the public internet.

References:

Nutanix Cloud Clusters (NC2) on AWS Documentation