This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pathology
[{'content': 'Inheritance pattern of ABO blood group system and HLA system \nSelect and explain. \nA. Pseudodominance, B. Autosomal dominant, C. Autosomal recessive, D. Codominant', 'role': 'user'}, {'content': 'Answer: D \nExplanation: "The genes that determine the A and B phenotypes are found on chromosome 9p and are expressed in a Mendelian codominant manner."', 'role': 'assistant'}]