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
Inheritance pattern of ABO blood group system is - 
Select and explain. 
A. Pseudodominance, B. Autosomal dominant, C. Autosomal recessive, D. Codominance
D: Codominance
Answer: D: Codominance 
Explanation: Ans. is 'd' i.e., Codominance