Which of the follwing description about BSR/RP mechanism is true? (Multiple choice)

Which of the follwing description about BSR/RP mechanism is true? (Multiple choice)
A . PIM-SM domain can have multiple C-BSR, but can only elect a BSR
B . BSR through the received C-RP data packet to collect C-RP information
C . BSR by flooding Bootstrap packets advertised BSR information and C-RP information to all router in PIM-SM domain
D . a C-BSR also can collect C-RP information through received C-RP data packets

Answer: ABC