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: Biochemistry
In translation process , proof reading of tRNA is done by: 
Select and explain. 
A. RNA polymerase, B. Amino - acyl-t - RNA synthetase, C. Leucine zipper, D. DNA
B: Amino - acyl-t - RNA synthetase
Answer: B: Amino - acyl-t - RNA synthetase 
Explanation: B i.e. Amino acyl t-RNA synthetase