This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of nucleic acids, Subject name: Biochemistry
Which of the following is a ribozyme? 
Select and explain. 
A. Peptidyl transferase, B. Elongation factor 2, C. Primase, D. RNA polymerase
A: Peptidyl transferase
Answer: A: Peptidyl transferase 
Explanation: Interestingly, some RNA molecules have intrinsic catalytic activity. The activity of these RNA enzymes, or ribozymes, often involves the cleavage of a nucleic acid. Two ribozymes are the peptidyl transferase that catalyzes peptide bond formation on the ribosome, and ribozymes involved in the RNA splicing.Ref: Harpers Illustrated Biochemistry, 30th edition, page no: 363