Option (E) tells you that Michelangelo's work has high artistic value. That is why it is not considered obscene in spite of having nudity. This weakens the argument since Michelangelo's work has something extra and the same may not be applicable to modern photography.
Even here we are assuming that work of contemporary artist is not as good as it is of Michelangelo. It may be that contemporart artists are as good as or even better, and therefore there work would be artistic as well
However from the sentence
"since even they would agree that Michelangelo's works of art, most of which depict nudity, are not obscene"
we get that Michelangelo was more artistic, and therefore A should suit more !!.
Consider following arguments:
As per A:
You: "Because modern artists work approach does not follow that of Michelangelo, I don't agree their work of nudity"
Author: "Why should their work approach follow Michelangelo, as long as they both contain nudity?"
In this argument you are lost!
Let us go with E:
You:"Michelangelo work contains high artistic values. Because modern artists work does not have high artistic values I don't approve of their work"
Author: "Hmmm...so for the government to support art that contains nudity, it should have high artistic values, no matter whose work it is"
Here you win.