In these lines from “On His Blindness,” what does the imagery best help to convey?
In the fullness of the years, like it or not,
a luminous mist surrounds me, unvarying,
that breaks things down into a single thing,
colorless, formless. Almost into a thought.

A
the half-light that is all that the speaker now sees

B
the speaker’s worn-out thinking processes

C
the speaker’s faded physical appearance in old age

D
the weather conditions in which the speaker finds himself