Which statement best describes a server type under an N-tier architecture?

Defining a server type as a group of servers at a specific layer omits the critical qualifier that those servers must share a unique role - location in a layer alone does not constitute a server type.

A single server with a specific role describes an individual instance, not a server type - N-tier is designed to support multiple servers per role for scalability and fault tolerance.

N-tier architecture organizes servers into logical tiers - such as presentation, application, and data - where each tier can contain multiple servers all performing the same unique role. This multi-server grouping by role enables horizontal scaling and redundancy, and is what defines a server type - the shared function, not the count or layer alone.

A single server at a specific layer is both too narrow in count and too vague in role definition to describe a server type in the context of N-tier architecture.