Labeling a simple song as AABA form indicates
A) the use of a chorus.
B) a polyphonic texture.
C) phrases 1,2,4 are similar.
D) loud/loud/soft/loud dynamics.
In poetry and also music, you can use letters to express rhythmic patters. Same letters express verses that rhyme. So using AABA means that phrases or verses 1, 2, and 4 rhyme.