Two siblings, Sarah and Tom are playing a simultaneous hit and tell game. Sarah can hit Tom or not and Tom can tattle on Sarah or not. Relative to no hitting and no tattling, if Sarah hits Tom, and he tattles they both experience a loss of 10. Not telling, gets Tom a bruise, a loss of 5 but Sarah gains 5. If he tattles untruthfully, he gets a gain of 5 and Sarah loses 5. If they get along, no one gets anything.
If Tom untruthfully tattles, what would Sarah's best response be?