Right answer is (b) Patented products can be manufactured by other companies once the patent is lost
To explain I would say: When new drugs are introduced, they are patented by brand-name drug companies. When these patents get expire, other companies can make drugs using the same active ingredient. These drugs are known as generic drugs. Generic drug companies must submit an abbreviated new drug application demonstrating that their products are bioequivalent to a drug product already on the market. Generic drugs are sold at much lower prices than the original one.