Which of the following is NOT one of the types of forwarding?

The correct option, which indicates the type that is not recognized as a standard switching method, is selective switching. The primary types of forwarding methods used in networking, specifically within Cisco environments, include process switching, fast switching, and Cisco Express Forwarding (CEF).

Process switching is the traditional method where the router processes each packet individually; this is generally the least efficient and can lead to high CPU usage due to the overhead involved. Fast switching was developed as an optimization to reduce this overhead, allowing the router to cache the destination address and streamline the forwarding process for subsequent packets. Cisco Express Forwarding (CEF) further enhances packet forwarding by creating a Forwarding Information Base (FIB) and a adjacency table, allowing for even more efficient handling of packets.

Selective switching, however, is not a recognized forwarding method in Cisco's architecture or in general networking. That’s why identifying it as the answer highlights a gap in common forwarding methods utilized in routers and switches. Understanding these fundamental concepts of routing and switching is essential for effectively operating and configuring network devices in an enterprise setting.