Yes, this is a school question, and yes I already know the correct possible answers (supposedly), so I'm not going to bother posting them. Instead, I just want to understand the meaning of this question. I know what class B addresses are, and what valid class B subnet addresses are. I guess one way to define my question is to ask why the answer "255.255.0.0" is wrong, necessarily? That seems to defy my understanding, or else some part of my brain is just not registering the question correctly.
Thanks in advance.