The correct answer is A. This excerpt illustrates the tediousness of life.
In this passage, Prufrock is basically saying that for him every day is the same. Because every day is the same, he has "known them all already." He says he knows the "evenings, mornings, afternoons" because each one is the same as the one that came before. Because every day is the same, and because nothing exciting ever happens to him, his life is montonous and boring.
Therefore, this passage illustrates the tediousness of life.