This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hematology, Subject name: Pediatrics
An afro-american kid of 6 years of age presented with abdominal pain, chronic hemolysis and abnormal RBC shape on peripheral smear. Most likely disorder responsible for this condition 
Select and explain. 
A. Trinucleotide repeat, B. Point mutation, C. Antibiodise against RBC membrane, D. Genetic imprinting
B: Point mutation
Answer: B: Point mutation 
Explanation: Diagnosis here is sickle cell disease results from point mutation ,results in substitution of valine for glutamic acid at 6 position of beta globulin chain. Reference: GHAI Essential pediatrics, 8th edition