This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Replication, Subject name: Biochemistry
Which is the only prokaryotic DNA polymerase with 5'-3' exonuclease activity? 
Select and explain. 
A. DNA Polymerase I, B. DNA Polymerase II, C. DNA Polymerase III, D. DNA Polymerase IV
A: DNA Polymerase I
Answer: A: DNA Polymerase I 
Explanation: DNA polymerase I 1st DNA polymerase discovered Only polymerase with 5'-3' exonuclease activity. DNA polymerase I 5' - 3' polymerase Polymerisation 3' - 5' exonuclease Proofreading 5' - 3' exonuclease Removal of RNA primer, DNA repair, nick-translation