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: Medicine
In Beta thalassemia, the most common gene mutation is - 
Select and explain. 
A. Intron 1 inversion, B. Intron 22, C. 619 bp deletion, D. 3.7 bp deletion
A: Intron 1 inversion
Answer: A: Intron 1 inversion 
Explanation: None