单项选择题IS - IS creates and maintains adjacencies and neighbor relations by using the Hello protocol. For the following options, which are Hello packets used in IS - IS?()
A. A generic Hello
B. Point - to - point Level 1, point - to -point Level 2, LAN Level 1, LAN Level 2
C. Point - to - point Level 1, point - to - point Level 2, LAN
D. Point - to - point, LAN Level 1, LAN Level 2