Which of the Following Would Be Considered Fair Use of Copyrighted

Which of the following would be considered fair use of copyrighted material?

A) A writer references a portion of a comedian's script in a book in order to demonstrate a key point in the book.
B) A writer copies a portion of a new book on chess in which he reveals the secrets in the competitor's book.He credits the original author.
C) A songwriter puts the words of a poem to a musical score.
D) A writer and biologist copy 30 diagrams from another textbook, citing the original author.