Shoshanna would have stood up and said, in a voice that's audible but not loud:
"I'm Shoshanna Fischer. I've learned that Muggles..." here she would have had to stop and think about it for a second, her mind going blank. "Um...I don't think I know much about Muggles," she'd finally admit, her face turning red. And she's really not lying, anything she might have learned about them through Olive or anyone else has completely left the building.