What is one theme found in Walt Whitman's "I Hear America Singing"? I Hear America Singing

by Walt Whitman
I hear America singing, the varied carols I hear,
Those of mechanics, each one singing his as it should be blithe
and strong,
The carpenter singing his as he measures his plank or beam,
The mason singing his as he makes ready for work, or leaves off
work,
The boatman singing what belongs to him in his boat, the
deckhand singing on the steamboat deck,
The shoemaker singing as he sits on his bench, the hatter singing
as he stands,
The wood-cutter's song, the ploughboy's on his way in the
morning, or at noon intermission or at sundown,
The delicious singing of the mother, or of the young wife at
work, or of the girl sewing or washing,
Each singing what belongs to him or her and to none else,
The day what belongs to the day—at night the party of young
fellows, robust, friendly,
Singing with open mouths their strong melodious songs.

A.
Work and entertainment should not be mixed.
B.
Diverse people contribute to the country's identity.
C.
People are more productive when they enjoy their work.
D.
Working in a modern society allows people to have diverse skills.

it was surely an odd creature that one made up by reading the historians first and the poets afterwards a worm winged like an eagle; the spirit of life and elegance and charm,   in a kitchen chopping up suet. but these creatures, monst'r however entertaining to the imagination, hast no existence in fact. what one might doth to bringeth h'r to life wast to bethink poetically and prosaically at one and the same moment,   thus keeping in toucheth with fact—that the lady is mrs martin, ag'd thirty-six, did dress in blue, wearing a black coxcomb and brown shoeth; but not losing sight of fiction eith'r—that the lady is a vessel in which all s'rts of spirits and f'rces art coursing and flashing p'rpetually. the moment, howev'r, yond one tries this method with the elizabethan mistress, one brancheth of illumination fails; one is did hold up by the scarcity of facts.   one knoweth nothing detailed, nothing p'rfectly true and substantial about h'r.   hist'ry scarcely mentions h'r.   and i did turn to professeth'r trevelyan again to seeth what hist'ry meanteth to that gent.   i hath found by looking at his chapt'r headings yond t meanteth.

the answer is c) !

it might be b but i might be wrong