Final answer:
The central theme of Carl Sandburg's "Chicago" is the personalities of cities, encapsulating the city's industrial vibrancy and resilience while also recognizing its issues.
Step-by-step explanation:
The central theme of the poem "Chicago" is b) The personalities of cities. Carl Sandburg's poem "Chicago" celebrates the dynamism and energy of the city, acknowledging its flaws while also admiring its vibrancy and strength. Sandburg personifies Chicago as the "City of Big Shoulders," suggesting its capability to carry the weight of industry, labor, and its people. Although the poem briefly touches upon the growth of cities and history, these are not the main focus. Instead, Sandburg reflects on the city's rough-and-tumble character, and its role as a hub for industry and agriculture, which in essence is a commentary on the city’s personality and spirit.