Answer:
B. the laborers' fundamental unity
Step-by-step explanation:
The majority of the laborers in the poem are happy as they work. One sign of their satisfaction in their efficiency is that they all sing as they work. The picture of the singing laborers is rehashed all through the poem to demonstrate the topic of happiness and satisfaction in work. Walt Whitman portrays this in the poem:
I hear America singing, the varied carols I hear...
The laborers have various voices and various songs. The lyric's storyteller depicts how every one of the laborers are "singing with open mouths their strong melodious songs."