Which statement best evaluates the organization of a piece of writing?

a. the author fails to provide adequate evidence to convince the audience that his claims are correct.
b. the book lacks transitions that would have guided the reader between topics; instead it feels like a jumbled mess.
c. the book contains several misspellings, typos, and grammatical errors that are very distracting to the reader.
d. the book fails to use citations throughout, leaving the reader to wonder where this information came from.