Explanation
									
									
										
A patent is an intellectual property right given by the government to an inventor for a new and useful invention or discovery. 
The invention or discovery must be novel, non-obvious, and useful to be eligible for a patent. This exclusive right granted to the inventor enables them to prevent others from making, using, or selling the invention without their permission for a limited period of time. 
Therefore, option A, "New and usual invention," is the correct answer.