September 2009, Sec1, #12. Please help me understand the right answer/diagram this

LSAT Determined

I'm having trouble with this question

beth.flanders

Here's what I came up with.

The purpose of art is to cause experts to debate...
P->D.

The argument indicates that the edifice has already caused debate and concludes that the edifice qualifies as art or that the edifice IS actually art.
D->QA.

We need to connect the purpose with what qualifies as art.
P->D
D->QA
Answer choice any object that fulfills the purpose of art qualifies as art.
P->QA.

Other Answer Choices:
A reverses the logic QA->D
B incorrect negation D->/QA
C is irrelevant P -> /opposed
E is irrelevant QA-> purchase