Theo factored a greatest common factor (GCF) of 4x^2y from the eapression 12x^2y^3 -20x^3y^2+32x^4y. What error did Theo make, if any?

Theo could have factored an additional y variable from the expression.
Theo could have factored an additional x variable from the expression.
Theo didn't make an error. He factored thecorrct GCF.
Theo could have factored a higher coefficient from the expression.

The error Theo made was that he factored out the GCF of 4x^2y incorrectly. The correct GCF should be 4xy.