Once every day (Monday - Friday, because Foster hates you) we bestow a comment with the title of Best of the Day. For humor or wisdom or, in today's case, good blind item detective work that yields... sexy results.
An embarrassing amount of info on 1 being Efron:
Ryan Pinkston, Matt Prokop and Sterling Knight have all been mentioned as roommates at some point. However Knight and Prokop often refer to each other as roommates in the press.
Sterling is from Sunny with a Chance (he's Chad Dylan Cooper) and was in 17 Again (Efron connection). He is 20. From his website: "Sterling is roomates with High School Musical 3: Senior Year's Matt Prokop."
Matt Prokop was in HM3 (Efron franchise connection) and is 19. He moved to LA from Texas at 16. Definitely struggling.
Pinkston is 21 and doesn't share any credits with Zach. I don't think it's him.
Lucas Grabeel was mentioned but he's 26 and was in all the HSM from the start. Same thing for Corbin Bleu - been there from the beginning. So I don't think either of those work.
In this scenario, it has to be someone who joined in after HSM 1 like Prokop in 3.
Personally I'd guess:
Zac Efron A
Matt Prokop B
Sterling Knight C
So, basically some hot barely-legal Disney franchise gay stuff. All brought to you by sleuthing commenters. Those that appreciate such things surely thank you. Just don't shake their hands.