I've come to the conclusion that it is not A) or D). You already proved that you can have a 19% drop rate so A's out. D's also out because the answer they are all wrong was nullified when A was proved as a percent. So from the remaining answers I pick C) 5.880% only because the math gets a little confusing after looking at it for a while. But I probaly got it wrong knowing my luck but I am glad to lose on a question from the god of Kingdom Hearts II, Tavrobel.

Ps: don't take this as kissing up, it's just meerly a compliment.