This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'The use of broad-spectrum antibiotics can produce a bleeding diathesis characterized by hematomas, hematuria, melena, and bleeding from the gums by decreasing the normal gut flora and inducing a deficiency of: \nSelect and explain. \nA. Vitamin A, B. Vitamin B1, C. Vitamin B6, D. Vitamin K', 'role': 'user'}, {'content': 'Answer: D \nExplanation: A deficiency of vitamin K, which can result from fat malabsorption, broad-spectrum antibiotics, or diffuse liver disease, produces a bleeding diathesis characterized by hematomas, ecchymoses, hematuria, melena, and bleeding from the gums. Laboratory tests reveal an increased bleeding with prolonged PT and PTT and normal bleeding time.', 'role': 'assistant'}]