After the repeated passage of black, tarry, and foul-smelling stools, catherine baldwin was diagnosed as having . this condition is caused by the presence of digested blood in the stools.

Black tarry foul-smelling stools refer to the upper GI bleed, as in gastritis, peptic or duodenal ulcer, esophagul varices or malignancy in the upper GI that leads to bleeding.

Explanation:

Ulcers or any other irritation in your esophagus or stomach known as gastritis can cause bleeding. When this blood mixes with digestive secretions and enzymes it takes on the appearance of tar, this change in color and consistency occurs because of oxidative chemical reactions. Sometimes, serious blood and circulation abnormalities in digestive system can cause black, tarry stools.

i think the answer is d.