About Oath Armor quest!

I have 3 questions:

1 - How do I define my sponsor?
2 - Can any member of the academy be my sponsor?
3 - Can I use the armor if I leave the academy?

Thanks for the anwsers ;)

#1 Someone with authority in your clan must do it.
#2 No, full clan member only and someone who isn't already a sponsor.
#3 Yes, until you remove it.

You don't, the person sponsoring you does. I believe the actual clan right for it is "master rights". Otherwise the option is greyed out.

Only someone in the main clan with the proper rights can do it, as long as they don't already have one. They can always sponsor someone long enough to do the quest, drop them and do another person, it doesn't mess up anything.

If you leave it works until you take it off, then you can't put it back on. If you graduate you can take it off and on all you want.