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 35 - year old male who had chronic duodenal ulcer for the last six years presents with worsening of symtomps loss of periodicity of symptoms, pain on rising in the morning sense of epigastric bloating and post - prandial vomiting. The most likely cause of the worsening of his symptoms is the development of ? 
Select and explain. 
A. Posterior penetration, B. Gastric outlet obstruction, C. Carcinoma, D. Pancreatitis
B: Gastric outlet obstruction
Answer: B: Gastric outlet obstruction 
Explanation: Ans. is 'b' i.e., Gastric outlet obstruction