Which of the following is a sentence fragment?

a. realizing you are getting older is sobering.
b. hiding in the tree fort he had built as a kid.
c. checking his mail each day was always fun.
d. knowing he would be late, she took a nap.

What does the excerpt tell about the narratos mental shift i suppose i shall have to get back behind the pattern when it comes night,and that is hard? @a.the narraor believes that the wallpaper is beatiful b.he believes that the woman in the wallpaper will attack him when he sleeps c.the narrator believes that he cant escape from the windws with the bars d.that the narrator was once behind the wallpaper