A.OSPF external LSAs are automatically flooded into all OSPF areas, unlike type 7 LSAs, which require that redistribution be configured.
B.External LSAs (type 5) are automatically changed to type 1 LSAs at ASBRs.
C.Type 5 LSAs are route summaries describing routes to networks outside the OSPF Autonomous System.
D.External network LSAs (type 5) redistributed from other routing protocols into OSPF are not permitted to flood into a stub area

A.Before sending traffic, it must first join  multicast group 239.1.1.1 by sending an IGMPv2 membership report to the default router on the local subnet.
B.It must send an IGMPv2 Request to Send  packet and then wait for an IGMPv2 Clear to Send packet from the IGMPv2 querier router on the local subnet
C.It may begin transmitting multicast traffic to the group only when there is no other host transmitting to the group on the local subnet.
D.It may transmit multicast traffic to the group at any time.