The Nurse Is Caring for a Patient on a Gastrointestinal

The nurse is caring for a patient on a gastrointestinal unit.Which patient statement should cause the nurse the most concern?

A) "My stool has been dark green and hard to pass lately."
B) "Lately, I've had two or three loose, sticky black stools every day."
C) "Usually I move my bowels every day and the stool is light brown."
D) "My stool is soft and dark brown; I usually move my bowels twice a day."