First of all, thanks for replying and not trashing this mail.
Bogus question. First I'd say that these days, using the term "IP protocol" still refers to IPv4, not IPv6 or both v4 and v6. Second, I can configure all six addresses on my local machine and still access the internet through a 7th IP.
Yes, you can, but can you use all of them to get Internet connection? I can set "e", but: on OpenBSD I can ping "e" and use it (route, use Internet) even when it's netmask is 255.255.255.0 (not 255.255.0.0 as you pointed), but I can't even ping it on other OS'es. (which is right? I guess the OpenBSD way, but why?) And "b" I can't nor ping, nor use (even on OpenBSD). How can you access internet through 7th IP? Isn't IPv6 link-local only available on direct links?
a and e are RFC1918 private address space addresses so they should not be used on the internet (an IP address ending in 0 can easily be valid with a given netmask (say 255.255.0.0 in the case of e)). b is, like you already pointed out, IPv4 multicast.
IMHO, "a" is ok, because it is valid IP, it is both routable and NAT-able. Or in other words, you can have Internet when your pc's IP is RFC1918.
Where did you find this quiz ? It's total rubbish if you ask me.
I find that question dumb, too. It's in one vortal, in country I live (ex-USSR). The author is complete moron. He even got named "selfish-bastard" IRL by RMS in conference about patents. The problem with this question is that I have to answer it, I have to choose only one variant and I must do it in next ~12 hours. Which would you choose? If I must choose one, I would take "b", because it seems "the right one". Of what I know about multicast - that IP is not usable, it's just virtual (as orientier) and only routers deal with them, but no PCs use it as it's IP. Please correct me if I'm wrong.
