What is the optimum distance for a person sitting using the Cisco TelePresence System 500?

A.	the camera can adjust automatically
B.	0.5 meters and 0.75 meters (1.5 and 2.5 feet)
C.	1.2 meters and 1.8 meters (4 and 6 feet)
D.	3.0 and 5.0 meters (10 and 15 feet)