Which two of the following statements regarding LDP are true? (Choose two.)

A.
LDP can also be used between nonadjacent routers using multicast LDP hello messages.

B.
LDP does not require periodic hello messages once the LDP session has been established between the LDP peers.

C.
LDP hello messages use TCP packets with a destination port number of 646.

D.
Multiple sessions can be established between a pair of LSRs if they use multiple label spaces.

E.
Per-platform label space can be identified by a label space ID of 0 in the LDP identifier field.