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
ABO blood groups inheritance is an example of - 
Select and explain. 
A. Mitochondrial inheritance, B. Allelic exclusion, C. Sex-linked inheritance, D. Co-dominance
D: Co-dominance
Answer: D: Co-dominance 
Explanation: . Co-dominance