Which device operates at Layer 2 of the OSI model?

A.
Hub

B.
Firewall

C.
Switch

D.
Router

Explanation:
Answer C is correct; A switch operates at layer 2 (data link layer) of the OSI model.

Incorrect Answers and Explanations: A, B, and D: Answers A, B, and D are incorrect. A hub operates at layer 1 (physical). Packet filter and stateful firewalls operate at layers 3 and 4, Circuit-Level Proxies (such as SOCKS) operate up to layer 5 (session), and application-layer proxies operate up to layer 7 (application).
Routers operate at layer 3 (network).