An Ad for a New Mouth Rinse Says That It

An ad for a new mouth rinse says that it "reduces plaque on teeth by 200%." What does this mean?

A) It means that one-fifth of the plaque is removed because 200/1000 = 0.2, or one-fifth.
B) It's nonsense because plaque is a categorical variable, so percents don't make sense.
C) It means that there is 2 times as much plaque before using the rinse as there is after using it.
D) It's nonsense because removing 100% of the plaque already removes all of it, and you cannot remove more than there was at the beginning.
E) It's nonsense because percents only make sense for counts, and amount of plaque isn't a count.