The answer is obvious. Maya scholarship application is approved. Quinn wouldn't do that, she wouldn't even think about it. Besides, Quinn wouldn't have the money for it. Also, Stephen seems to know Priscilla, and he would certainly know then, so it would be Quinn.
Quinn knows where Sage came from. She's been at college for a while and must have exchanged a word or two with Sage's parents. Be it just a hello or other irrelevant phrases. But that would familiarize Stephen with Quinn's voice.
Considering the facts, there are more arguments against than for.