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: Surgery
A 40-year old male presents with history of vomiting of blood 2 hours ago. The volume of vomitus was estimated to be 500 ml. His BP was 90/58 mm Hg and pulse was 110/min. On abdominal examination, the spleen was palpable 5 cm below the costal margin. The most likely cause of the bleeding is 
Select and explain. 
A. Poal hypeension, B. Gastric ulcer, C. Duodenal ulcer, D. Drug-induced mucosal erosion
A: Poal hypeension
Answer: A: Poal hypeension 
Explanation: Ans. a. Poal hypeension