Hi,
The answer D is incorrect because there is no such thing as "IPv6 stateful autoconfiguration" - at least this is not an official name of any known mechanism. We have IPv6 stateless configuration, and then DHCPv6. That is why I would pick answers A and B.
Just a nitpicking remark: It is actually DHCPv6 that would qualify as a stateful IPv6 autoconfiguration mechanism, but it has never been officially called that way. I would personally challenge the authors of this quiz question to change the option 'D' to something else, as 'D' can be misunderstood for DHCPv6.
Best regards,
Peter
