Actually Noya is correct, for this answer.
Your answer actually would be is.
E x p l a n a t i o n : -
You'll actually have to stay in a Associate's collage for at least for two to three years... which actually if you write "Is an postsecondary is a associate degree"? which- it is an a Associate degree.
Hope It Helps!
A n s w e r e d : - ᴀᴅʀɪᴀɴɴᴏɪʀ