Question

Question was provided via image upload.

Explanation:

Analyze the definition of an Autonomous System (AS)

An Autonomous System (AS) is a fundamental building block of the Internet's routing architecture. It is defined as a collection of connected Internet Protocol (IP) routing prefixes under the control of one or more network operators on behalf of a single administrative entity or domain that presents a common, clearly defined routing policy to the Internet.

Evaluate the given options

• Option A suggests an AS must use a single type of routing protocol throughout its entire infrastructure. This is incorrect; an AS can run multiple different Interior Gateway Protocols (IGPs) internally (such as OSPF and IS-IS).
• Option B describes a network segment isolated for security, which refers to a DMZ or isolated VLAN, not an AS.
• Option C describes an offline or air-gapped network, which does not define an AS in global routing.
• Option D states that an AS is a collection of routers under the administrative control of a single entity, sharing a common routing policy. This matches the standard networking definition.

Answer:

• (A) A network that uses a single type of routing protocol throughout its entire infrastructure
• (B) A network segment that is isolated from the rest of the network for security purposes
• (C) A network infrastructure that operates independently of the Internet
• (D) A collection of routers under the administrative control of a single entity, sharing a common routing policy (Correct answer)