Which two actions can prevent interface trunking?

For security reasons, the IT manager has prohibited users from dynamically establishing trunks with their associated upstream switch.

Which two actions can prevent interface trunking? (Choose two.)
A . Configure trunk and access interfaces manually.
B . Disable DTP on a per interface basis.
C . Apply BPDU guard and BPDU filter.
D . Enable switchport block on access ports.

Answer: AB

Explanation:

The Dynamic Trunking Protocol (DTP) is used to negotiate forming a trunk between two Cisco devices. DTP causes increased traffic, and is enabled by default, but may be disabled. To disable DTP, configure "switchport nonegotiate." This prevents the interface from generating DTP frames. You can use this command only when the interface switchport mode is access or trunk. You must manually configure the neighboring interface as a trunk interface to establish a trunk link, otherwise the link will be a non-trunking link. Reference: http://www.ciscopress.com/articles/article.asp?p=2181837&seqNum=8