Which statement tells where a paragraph break should be in this dialogue?

"My, what a large collection of books you have. Thank you for donating them," said the librarian. "Oh, thank you for taking them," said the woman. "We're moving and just can't keep them all."

A.
A paragraph break should come after the word librarian and after the word woman.

B.
A paragraph break should come after the word woman.

C.
A paragraph break should come after the word librarian.