单项选择题
A. CompanySwitch（config-if）#switchport trunk encapsulation dot1q
B. CompanySwitch（config-if）#switchport trunk encapsulation itef
C. CompanySwitch（config-if）#switchport trunk encapsulation fddi
D. CompanySwitch（config-if）#switchport trunk encapsulation isl
E. None of the other alternatives apply
单项选择题 Switch R1 has been configured with DTP using the desirable option. Which statement describes Dynamic Trunking Protocol （DTP） desirable mode？（）
多项选择题 The core Company switches are configured to use 802.1Q trunks. Which three statements are correct with regard to the IEEE 802.1Q standard？（）
多项选择题 Refer to the exhibit. On the basis of the output generated by the show commands， which two statements are true？（）