A Woman Was Anemic During Her Pregnancy

A woman was anemic during her pregnancy.She had been taking iron for 3 months before the birth.She gave birth by cesarean 2 days ago and has been having problems with constipation.After assisting her back to bed from the bathroom,the nurse notes that the woman's stools are dark (greenish-black) .The nurse:

A) Performs a guaiac test and records the results
B) Recognizes the finding as abnormal and reports it to the primary health care provider
C) Recognizes the finding as normal as a result of iron therapy
D) Checks the woman's next stool to validate the observation