I would have done 3, definitely. And then reviewed my "friendship" group.
However, I do think it matters whether the group knew you were taking the dog with you, or if you just turned up with the dog in tow.
If they didn't know the dog was coming, then maybe this was a passive-aggressive action to make it known they didn't approve.
But if they knew in advance, and didn't approve, or welcome the dog (weird people, if that's the case - personally I'd take the company of a dog over the vast majority of humans any day), then you'd have hoped that at least one of the group that you did know well, would have said something to you ahead of the walk, rather than ostracising you at lunch time.