The Chinese government recently issued a ratification of its plan to create a symbolic administrative region called Sansha to manage three archipelagos, including the Paracel and Spratly Islands. This sanction created a lot of tension in Vietnam, leading up to demonstrations from Vietnamese people around the world, who believe that the Paracel and Spratly Islands belong to Vietnam. Whose properties are these two islands, which is known to possess a large amount of oil and natural gas?