Although the question has been already asked before on BTG(https://www.beatthegmat.com/1000-cr-test ... t1835.html), I am not convinced with the explanation and OA. I searched on the net, but all-in-vein. I don't know the OA too, so let's discuss.

In many surveys, American consumers have expressed a willingness to spend up to 10 percent more for products that are ecologically sound. Encouraged by such surveys, Bleach-O Corporation promoted a new laundry detergent, Bleach-O Green, as safer for the environment. Bleach-O Green cost 5 percent more than typical detergents. After one year, Bleach-O Green had failed to capture a significant share of the detergent market and was withdrawn from sale.

Which of the following questions is LEAST likely to be relevant in determining the reasons for the failure of Bleach-O Green?

(A) How effective as a detergent was Bleach-O Green?

(B) How many other detergents on the market were promoted as safe for the environment?

(C) How much more did Bleach-O Green cost to manufacture than ordinary detergents?

(D) To what extent did consumers accept the validity of Bleach-O Green advertised and promoted to consumers?

(E) How effectively was Bleach-O Green advertised and promoted to consumers?