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
Which of the following is caused by deletion of all four alpha globin genes 
Select and explain. 
A. Beta thalassemia major, B. Hb Bas, C. HbH, D. adeg thalassemia trait
B: Hb Bas
Answer: B: Hb Bas 
Explanation: Ans. is 'b' i.e., Hb Bas