The correct answer is indeed a rhetorical question.
Rhetorical questions are those questions which don't necessarily need an answer. They just show us what somebody is thinking about, and it doesn't mean they want their question answered. This is what the excerpt above is about.
Answer: The theme of the poem is taking joy in one's work and also for being productive.
Explanation:
The theme of the poem "I Hear America Singing" is simply about taking joy in the work thatnines does and being productive.
The work of the people in different occupations were identified by Whitman. He identifies the works of the carpenter, mason, shoemaker, woodcutter, boatman etc.
This poem shows the joyous reflection of Americans, and how they go about their daily activities happily, healthy, and have a sense of contentment.