Hmm...Very good question. I took 4.22 minutes to complete this and got the answer right

My reasoning is as follows:
Fact 1: Sales of Luxury Goods decreased immediately after the stock market crash
Fact 2: Sales of Luxury Goods doubled since the immediate decrease
Fact 3: To return to pre-recession rate, retailers must offer significant discounts on Luxury Goods for recession-wary consumers.
In "Fact 2", the author mentions that the sales of Luxury Goods have since doubled. He means, the sales have doubled from the "time immediately after the stock-market crash". The author is not comparing the sales with pre-market-crash period.
Option (A) : No relevance
Option (B) : Even though, this option looks like an answer, it doesn't talk about sales at all
Option (C) : No relevance
Option (D) : This option rightly answers our concerns about Fact 1, Fact 2 and Fact 3
Option (E) : This option states a generic statement which cannot be strongly inferred from the argument above.
So, the correct answer is Option (D)