Read the poem.
the lesson by paul laurence dunbar

my cot was down by a cypress grove, and i sat by my window the whole night long, and heard well up from the deep dark wood a mocking-bird's passionate song. and i thought of myself so sad and lone, and my life's cold winter that knew no spring; of my mind so weary and sick and wild, of my heart too sad to sing. but e'en as i listened the mock-bird's song, a thought stole into my saddened heart, and i said, "i can cheer some other soul by a carol's simple art." for oft from the darkness of hearts and lives come songs that brim with joy and light, as out of the gloom of the cypress grove the mocking-bird sings at night. so i sang a lay for a brother's ear in a strain to soothe his bleeding heart, and he smiled at the sound of my voice and lyre, though mine was a feeble art. but at his smile i smiled in turn, and into my soul there came a ray: in trying to soothe another's woes mine own had passed away.

what does the bird’s song symbolize for the speaker? a peace and prosperity b frustration and longing c hope and comfort d mercy and forgiveness