"A" is a first class according to re-booking provisions of the DL CoC. The only indication a PAX would have at time of purchase is the title of the Fare rule. Which isn't really bound to any provision of the CoC. You might be able to figure it out after the purchase from the receipt. Depending on what channel you purchased the tickets from you may not see the actual receipt until after the 24hr refund period.
It seems like a pretty clear violation of Unfair and Deceptive Trade Practices rules from the DOT. I'd like to see someone nail DL on it next time it comes up.