What is the leveling process for the Cisco TelePresence System 1000 frame?

A.
With only one display, there is no need to level the frame before attaching it to the wall

B.
Attach the frame to the wall and level the frame by raising or lowering the feet

C.
Place a level on the middle and upper crossbars and adjust the feet as necessary to ensure that the frame is horizontally level

D.
Place a level on the side of the frame and adjust the feet as necessary to ensure that the frame is vertically level