Question: What type of IP address is contained in the MBMS-BMSC-SSM-IP-Address AVP?
Option 1: IPv6 address
Option 2: Either IPv4 or IPv6 address, but not both
Option 3: IPv4 address only for single stack BM-SC and either IPv4 or IPv6 for dual stack BM-SC 
Option 4: Both IPv4 and IPv6 addresses
Explanation: The MBMS-BMSC-SSM-IP-Address AVP contains the value of BM-SC's IPv4 address for Source Specific Multicasting, specifically for single stack BM-SC it is IPv4 only or dual stack BM-SC includes this AVP.