Regarding BGP reliable routing updates, which of the following description of is ture?

Regarding BGP reliable routing updates, which of the following description of is ture?
A . BGP works on top of UDP, and the transport layer protocol is 179
B . BGP does not need to periodically advertise routing information
C . BGP sends complete routing table information every time a route is updated
D . BGP uses multicast updates

Answer: B