Because there is a lack of a single factor to appraise the art against, calculating the market value of art is subjective.A 5 second scan of answer choices gives us no clear split : apart fromsome active passive issues
Lets get to meaning of the sentence
literally author wants to convey : calculating the value of art is subjective and he provides a reason: the art cannot be appraised against any single factor
note while inferring the meaning only we see idea is clearly stated if we keep everything as it is ,Now lets attack the choices
A) A. Because there is a lack of a single factor
to appraise the art against, calculating the market value of art is subjective. : jumbling the sentence keeps us to an open ended question appraise the art form against what ???
B.
Subjective is to calculate the market value of art because a single factor is lacking against which the art can be appraised. : shifting the sentence to passive construction changes our intended meaning.
C.
It is subjective to calculate the market value of art because against no single factor can the art be appraised. : hold for now
D. To calculate the market value of art is subjective because there is no single factor that the art can be appraised
against. : sentence ending with preposition red flag in GMAT
E.
Calculating the market value of art is subjective because there is no single factor against which the art can be appraised Now between C and E
E is active voice clearly stating our inferred idea in few words
C is passive and takes more word to state the idea and has a subtle meaning change
we can always say :"calculating market value of art is subjective" has different meaning than it is subjective to calculate the value of art
So My Take E