Read this passage from “The Secret Garden” carefully.

“Then Mary knew Dickon had meant the picture to be a message. He had meant that she might be sure he would keep her secret. Her garden was her nest and she was like a missel thrush. Oh, how she did like that queer, common boy!”

Which theme is best developed by this passage?

(A) The secret garden is a place for healing and growing

(B) The secret garden is a magical place

(C) Happiness depends upon helping others

(D) Secrets are dangerous