By asking if anyone will find out, you are basically saying yes. When saying I really shouldn't do it, you are not giving a concrete refusal. It also sounds like you maybe want to. When saying your brother wouldn't want to, you are not saying no, just stating something someone else said. A would be most effective since it is a clear and concrete refusal.
The baby could have respiratory problems from the smoke as well as birth defects. Drinking could also cause birth defects and some times even a miscarriage if the alcohol is abused enough. Over all, the baby could be severely hurt.
