What effect does the symbol have on the meaning of the passage from "here is new york"?

the commuter is the queerest bird of all. the suburb he inhabits has no essential vitality of its own and is a mere roost where he comes at day’s end to go to sleep.

a. the symbolism of the suburbs as a “roost” expresses the safety and comfort of the commuter’s home.

b. as birds are inherently pests, the writer uses symbolism to express his view that commuters offer nothing positive to new york.

c. the symbol of commuters as birds illustrates how they come and go without ever experiencing the city.

d. by describing the commuter as a bird, the writer emphasizes the freedom of commuters who can come and go from the city as they .