I disagree, I think the right choice is A
E has nothing to do with the health problem. All that E is going to ensure is that "there is no evidence of health problems" as the spokesperson assumes. Lack of evidence, however, does NOT mean that there are no health issues. There are plenty of things around us that were true, but people didnt have hard n fast evidence to prove it (think back to 15th century)
B - Standards for safety also have nothing to do with reality. If there's no evidence (as the spokesperson says) gov't may not have the ability to put in place standards prohibiting the chemical just based on the gut feeling, so it'll could issue a "safe" guidance for the lack of conclusive evidence. Again, there are a number of examples where safety standards changed overtime (FAA safety rules, Smoking in public places, etc.)
A - negates any reasonable possibility that there are health risks tied to this chemical. 20 years are reasonably sufficient for the effects to surface.
