An engineer requires a switch interface to actively attempt to establish a trunk link with a neighbor switch. What command must be configured? 

Answer options:

A. switchport mode trunk
B. switchport mode dynamic desirable
C. switchport nonegotiate
D. switchport mode dynamic auto

B

Reference: https://www.ciscopress.com/articles/article.asp?p=2181837&seqNum=8#:~:text=switchport%20mode%20dynamic%20auto%3A%20Makes,to% 20trunk%20or%20desirable%20mode.&text=switchport%20mode%20dynamic%20desirable%3A%20Makes,link%20to%20a%20trunk%20link .