Why Did Kornberg Initially Think That the Exonuclease Activity He

Multiple Choice

Why did Kornberg initially think that the exonuclease activity he found in his DNA polymerase preparations was a contaminating enzyme?

A) The action of exonucleases is a lot like endonuclease.
B) The action of exonucleases is so dramatically opposed to the activity of DNA polymerases, to synthesize DNA.
C) The action of exonucleases is exactly like the action of DNA polymerase.
D) Purification was so difficult.
E) Enzymes can often run the reverse reactions.