How were state constitutions helpful to the writing of the U.S. Constitution? A. The state constitutions contained no guaranteed rights, so the authors of the U.S. Constitution left them out. B. Most states had learned that having a strong central government was a mistake. C. Small and large states readily agreed on how to set up a national legislative body. D. The authors of the state constitutions had learned lessons that were useful in writing a new U.S. Constitution.