Which of the following is a symptom of hematemesis?

Hematemesis refers to the vomiting of blood, which is a direct indication of bleeding in the upper gastrointestinal tract. When an individual experiences hematemesis, the primary symptom is the expulsion of blood through vomiting. This can range from bright red blood, indicating recent bleeding, to coffee-ground-like vomitus, which signifies that the blood has been present in the stomach for some time and has begun to digest.

Symptomatically, while dark stool can be related to upper gastrointestinal bleeding (and is known as melena), it is not y a direct symptom of hematemesis since it involves the passage of blood through the bowel and not vomiting. Coughing and difficulty breathing are symptoms related to respiratory issues rather than hematemesis. Therefore, the correct letter choice, which is the act of vomiting blood, directly corresponds to the definition of hematemesis, making it the only appropriate response to the question.