Now, will you: A. Apologize and/or Make excuses B. Ask her to join in (Go for Broke) C. Ask her to call the rest of the sisters (Push your Luck) D. Bulls**t your way through clever troll logic & such to overwhelm her reasoning (Rapidfire Lying & Word manipulation) E. Other
Regardless of choice, the first step would be to revel in that hilarious face she's making. (Yanno, assuming you're a bit of a butthead to begin with to be going at her sister where she can walk in so easily.)