What is the purpose of a trunk port?

A.
A trunk port carries traffic for multiple VLANs.

B.
A trunk port connects multiple hubs together to increase bandwidth.

C.
A trunk port separates VLAN broadcast domains.

D.
A trunk port provides a physical link specifically for a VPN.

Explanation:
Ethernet interfaces can be configured either as access ports or trunk ports. Trunks carry the traffic
of multiple VLANs over a single link and allow you to extend VLANs across the network.

Reference:
http://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/configuration/guide/cli/C
LIConfigurationGuide/AccessTrunk.html