You are a network administrator at Certkiller . You want to configure the Catalyst 3524 switch to trust the CoS of the device attached to the Cisco 7060 IP phone.
What command would you use?

A.
set port priority extend trust

B.
switchport priority extend trust

C.
set port co 2/1 trust-ext trust-cos

D.
switchport cos 2/1 trust-ext trust-cos

Explanation:
Quality of Service on Catalyst 2900 XL and 3500 XL Series Switches Frequently Asked Questions
Q. Can I re-classify Class of Service (CoS) value of data generated from a PC connected to an IP phone which is attached to the Catalyst 2900 XL and 3500 XL series switches?

A. Yes, you can configure the interface level switchport priority extend trust command. This feature instructs the first Cisco IP phone to trust the dot1p tag received from the phone or any device connected to it on the phone’s secondary port. This command needs to be used with caution. If the user connects a workstation which sets the tag to the IP phone, the data traffic from the user gets the user set priority. It has a negative impact on the quality of the voice.
http://www.cisco.com/en/US/partner/products/hw/switches/ps607/products_qanda_item09186a0080116ffe.shtm l