Article 6, paragraph 1, of the Patent Law stipulates that an invention-creation made by performing the tasks of the entity or mainly utilizing the material and technical conditions of the entity is a service invention-creation. The right to apply for a patent for a service invention-creation belongs to the unit; After the application is approved, the entity shall be the patentee. "So item A is correct. Article 6, paragraph 3, of the Patent Law stipulates: "Where an invention-creation is made with the material and technical conditions of the entity, the entity and the inventor or designer have a contract stipulating the right to apply for a patent and the ownership of the patent, such agreement shall prevail. "Therefore, item B is correct. Paragraph 1 of Article 9 of the Patent Law stipulates: "Only one patent right can be granted to the same invention-creation. However, if the same applicant applies for a patent for utility model and a patent for invention at the same time for the same invention-creation on the same day, and the previously obtained patent right for utility model has not been terminated, and the applicant renounces the patent right for utility model, the patent right for invention may be granted. "Therefore, option C is correct and item D is wrong.