The answer would be : C. Manufacturers only
The otc product refer to 'over the counter' Medicine Product. These types of medicine products could be sold to a customer without a prescription so the Retailers does not really have to checked the efficiency of the Product for each consumer
The Supremacy Clause is a clause within Article VI of the U.S. Constitution which dictates that federal law is the "supreme law of the land." ... Under the doctrine of preemption, which is based on the Supremacy Clause, federal law preempts state law, even when the laws conflict.
Some are rumours or false stories