here is the full passage for this question
Richie had felt a mad, exhilarating kind of energy growing in the room. . . . He thought he recognized the feeling from his childhood, when he felt it everyday and had come to take it merely as a matter of course. He supposed that, if he had ever thought about that deep-running aquifer of energy as a kid (he could not recall that he ever had), he would have simply dismissed it as a fact of life, something that would always be there, like the color of his eyes . . . .
I believe the answer is: b.Childhood has a magical quality that slips away.
From the excerpt, we can see how Richie is mesmerized by the type of energy that he as a child could have with the things that exist in the childhood room. He probably wondering how such simple things could bring happiness to children while adults cannot achieve the same level of happiness with more extravagant things.
