Organize the following polynomial expressions from least to greatest based on their degree:
1. x+2 x y z
II. 3x+y+z
III. x^3 y+y^2 x-3 x+4
IV. 9x^3 y z
II, III, I, IV
III, I, IV, II
I, II, IV, III
II, I, III, IV
