Task: Question Answering
Input (English): Question: The proofreading activity of the DNA Polymerase is an activity: 
 Options:  <1> 5'-3'Exonuclease. <2> 3'-5'Exonuclease. <3> Polymerizing 5'-3 '. <4> Endonuclease. <5> Transesterifier.
Output (English): 2