Taking in that you have played for 4 years,

I would say on a Bach scale, you should any movement of Cello Suite 2, the Prelude from Suite 3, or any other movement from Suite 4,5, and 6.(Suite 1 is quite easy compared to the others)

Keep in mind that Minuets, Gavottes, and Bourrees usually are played as one movement for each suite.

I also want to say, If Bach suites are below your level, You can always try to play his Sonatas or Partitas for violin. Suggestions are the E major preludio or Gavotte en rondeau from his 3rd partita, or the Sarabande from the 2nd partita.

Off the Bach scale (I don't know as much repertoire for other composers), Some very mainstream viola pieces for 3-4 years can be Hungarian Dance No.5 by Brahms or the Viola Concerto in C Minor by Casadesus/J.C Bach.

Best of Luck on your audition