I believe the answer is B.) The unrhymed, non-rhythmic structure of the poem creates a loose, free feeling of being an individual in America.
Explanation: Whitman’s tone throughout the poem is rather reflective and accepting of what has come to pass in his life. He seems to be happy as seen it the begging on the poem; “I celebrate myself, and sing myself”. He is enjoying the little things in life and describing in detail his freedom to “loafe”, which means to be lazy and relax.