Nearest the concrete is a figurative way of saying what

adjective. constituting an actual thing or instance; real: a concrete proof of his sincerity. ... representing or applied to an actual substance or thing, as opposed to an abstract quality: The words “cat,” “water,” and “teacher” are concrete, whereas the words “truth,” “excellence,” and “adulthood” are abstract.

we need the passage first

i believe that the answer is b! i hope i out!