In Response to a Nurse's Question About Bowel Function, a Client

In response to a nurse's question about bowel function, a client shares that sometimes the feces are greenish black in color.Which answer by the nurse is correct?

A) "Large amounts of dairy products can cause your stools to turn green."
B) "If you take iron tablets, your stools can become greenish black."
C) "Typically our diet has very little to do with the color of our stools."
D) "Eating green foods, such as spinach, can cause your stools to have greenish black streaks."