More than any other single element, the increase in art

Highlighted portions are where I disagree. my main point of concern in the sentence.
1 Other Single Element
2 Has been. [ Art is singular and not plural.]

(A) More than any other single element, the increase in art prices has been responsible for
(B) More than any single element, the increase in art prices has caused (C) More than any other element, the increase in art prices have been responsible for
(D) The increase in art prices, more than any single element, has been the reason for
(E) An increase in the price of art works have been responsible, more than other elements, for

A and B is narrow. I would choose A Since the effect that Art price increase is the single most important contributor to the effect makes More than any other more effective.