I'm taking a test and have to guess the right answer to the question after the article. Article: Maybe you've just invented something better than the iPhone or a solar-powered car. You don't want anyone to steal your design. What should you do? Patent it! Patents are the best way to get credit for your work and help others continue advancing in that field. Here's what you need to know. A patent gives you the right to an invention. The patent protects its owner, which means the invention can't be copied or sold without their agreement. In exchange, the owner must reveal information about the invention. This contributes knowledge that helps other inventors improve on their own research. A patent usually lasts about 20 years. The first step to getting a patent is the application. The person applying must name the invention, explain its use and describe it clearly. The invention must be practical and contain some new characteristic -- something that hasn't been seen or used before. But not everything "new" can be patented. Many countries don't allow patents on things like new concepts, scientific theories, medical procedures or substances already found in nature. You may not be able to see patents, but they're connected to nearly everything. There are patents on things you use every day, like plastic, medicine and your computer. There are patents on things that are unavailable on the market, too. Apple is well-known for its patents on potential products, such as the "iBike" or the "iKey". Of course there are also patents on inventions like this. Take the anti-eating face mask for example. This _ locks around your head with a metal cage covering your mouth. You can breathe and speak, but you can't eat! Although many patented inventions can be failures, there's plenty of room for success. So if you have a cool invention, try to patent it. Question: The purpose of writing this passage is to _ . Options: A: advertise B: persuade C: warn D: inform
D