I have 2 questions-

1. How can we tell that the support is strong in this? Just because the premises support the conclusion?

2. This may be getting ahead of myself- but how do we know that number 2. and 3. of the premises are the only options? Is it because it says "members" and then "all other members"?

I just want to make sure I am not missing anything.

How do we get to that formal logic rule? I do not understand how it can be almost predicted what the rule should look like, before we get to that rule