I chose "b" since that is the SMART thing to do. Surely, if you have any intelligence, you can realize that for yourself too.
It wasn't to say he's stupid. It was to say that if he's smart (and he's given indication that he is, by his own direct words), that he should be able to come to the same conclusion to the point that I was making. Anyone, really, should come to that same conclusion, if they think about it (albeit some having to think harder than others, and that's not a hint, just a reality of life).
Edit: Added note, if I'm gonna call someone stupid.. There won't be any doubt that I'm doing it. I say what I mean and mean what I say.
Sometimes people say things with double meanings, I *TRY* to avoid saying things like that but obviously I don't always succeed. My mistake on not clarifying what I meant the first time.