What is "patent exhaustion"?

Patent exhaustion, often referred to as the "first sale doctrine," is a legal principle that arises after a patented item is sold to a buyer. It allows the buyer to utilize, resell, or otherwise dispose of that item without infringing on the patentholder's rights. Once the patented item is sold, the patent owner can no longer impose restrictions on how that specific item is used or transferred by the purchaser. This doctrine is essential because it promotes the free movement of goods in the market and prevents patent owners from controlling the item indefinitely after the initial sale.

In the context of the other choices, the first option, which suggests that patent exhaustion enhances a patent owner's rights, misunderstands the nature of the doctrine. The second choice implies that patent exhaustion prevents resale, which contradicts the principle's core purpose of allowing resale and use. The last option discusses renewing patents, which is unrelated to the concept of patent exhaustion, as it pertains to maintaining patent rights rather than the effects of selling a patented item. Thus, option C accurately represents the principle of patent exhaustion.