- (A) This seems to be suggested by the saying that, "What the valuation conventions were for...goods for sale is also uncertain. It is possible that their probable values were much lower than their actual market values." In other words, the author seems to be saying that the valuation conventions were uncertain but perhaps important to deciding how this stuff was valued. I'll keep this.
(B) I don't think "income tax returns" is ever mentioned in the passage. Eliminate.
(C) We are never comparing tobacco vs. alcohol in this whole debate, just comparing "goods for sale" to "bank balances or stocks". Eliminate.
(D) The author actually suggests the opposite, though we don't actually know for sure. If bank balances were "considered at full face value," we might say that the total probate valuations would be less valuable than those who had goods for sale. In addition though, we must realize that we are talking about "total probate valuations" and this seems to be a bit strong. Eliminate.
(E) We know nothing about if the goods were held by merchants or by bankers and how this affects anything. Eliminate.
So (A) it is!