In the last stanza, the words "I know why the caged bird sings, ah me" function as a way of —
A.
​​​​​​​contrasting the bird's song with the song the speaker sings in the poem

B.
​​​​​​​indicating the importance of being happy no matter the circumstances

C.suggesting that the speaker and the bird share reasons for singing sorrowful songs
D.showing that the speaker knows which parts of the bird's anatomy create its vocal skills