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
Mutation in sickle cell anemia is 
Select and explain. 
A. Silence, B. Missense, C. Non-sense, D. Frame-shift
B: Missense
Answer: B: Missense 
Explanation: Missense mutation - Sickle cell anaemia.
Non-sense mutation - Beta thalassemia.