Cisco Certified Network Associate (CCNA) 200-301 — Question 840

The correct answer is A. Option A: switchport mode trunkswitchport trunk native vlan 321switchport trunk allowed vlan 100,200,300

Explanation

A trunk carries traffic for multiple VLANs between network devices. Frames in the native VLAN are untagged by default on an 802.1Q trunk. A VLAN creates a separate Layer 2 broadcast domain on switched infrastructure.