"How did you know—" Professor McGonagall spluttered, and Hermione was about to speak when Mayumi interrupted.
"Someone's most likely going to steal the stone." She said, in a surprisingly calm and faint voice. Professor McGonagall looked as if she's about to interrupt but Mayumi beat her to it.
"I'm not that much of a dog person, professor, and plants seems to die whenever I touch them." Mayumi paused, "Harry is a good seeker and Ron is excellent at chess, and they clearly has experiences with trolls." Their head-of-house looks a little stunned now. "Oh, and I really love doing riddles in my free time."