Zacharias didn't need to look around with one little comment he could make every assumption he needed to figure this out. "Way to show your hand so soon." He nearly applauded her for it, but that might be a bit too much. Instead he just smirked shaking his head. "You have absolutely nothing because my sister is a Smith and a Burke and what are you?"
His father might have been a lot of horrible things, but he had always been a very good politician - one that did just as well for himself when the Ministry was overturned than any other time. His mother could be thanked for a large part of that as well, but he never felt any inclination to do so before so he wasn't going to start now. Certainly not over something so petty.
"Because I can tell you what I am. Bored and bothered that you're wasting my time." And totally ruining his zen for the morning, but he wasn't going to give her that piece of information. Marietta could think whatever she wanted about what he was up to last night.