This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Blood, Subject name: Pathology
Chromosome for ABO gene is? 
Select and explain. 
A. 9q, B. 10p, C. 11q, D. 12p
A: 9q
Answer: A: 9q 
Explanation: Ans is 'a' i.e. 9q * The ABO gene (Histo-blood group ABO system transferase enzyme) resides on chromosome 9 at the band 9q34.2.Also know* Gene for Rh antigen is located on Chromosome-1