What is most closely the significance of the phrase "the late steamer Big Missouri worked and sweated in the sun" in the following passage (paragraph 29)?
Tom gave up the brush with reluctance in his face, but alacrity in his heart. And while
the late steamer Big Missouri worked and sweated in the sun, the retired artist sat on
a barrel in the shade close by, dangled his legs, munched his apple, and planned the
slaughter of more innocents. There was no lack of material; boys happened along
every little while; they came to jeer, but remained to whitewash.
A. Ben is finding the fence job to be a lot easier than Tom did.
B. A steamboat coming down the Mississippi is running slow due to the heat.
C. Ben is no longer pretending to be a boat because he is now whitewashing the fence.
D. Tom has taken over the role of captain on the Big Missouri.