Alex is writing a narrative about the day his baby sister was born. Read this paragraph from the story.

My mom was lying in a hospital bed, holding a tiny, writhing baby with a giant red mouth. It was just as ugly as I’d thought it would be. But then my mom smiled and said, “Come hold your little sister, Alex.” My sister. Mom placed her in my arms, and suddenly the idea of a baby in the house didn’t seem so awful.

How does the writer use relevant details to develop the theme of accepting change?

A.
He includes details about the relationship between the mother and son.
B.
He provides details showing a change in Alex’s attitude after he meets his new sister.
C.
He includes details that explain how hard it is to accept a newborn when you’re only a kid yourself.
D.
He uses descriptive details that show Alex to be resentful of the new baby and how it will disrupt his life.