During the U. S. battle with a European country, the U. S. Navy used to advertise posters throughout the country as a recruiter. The most famous ad at the time was this: the U. S. Navy ’s mortality rate was lower than that of New Yorkers. "According to statistics, now the death rate of New Yorkers is 16% per year, and despite the wartime, the death rate of U. S. Navy soldiers is only 9%. ". If the above information is true, which of the following can explain the seemingly skeptical conclusion? ['During the war, as part of the navy carried transportation tasks and did not directly participate in the war, the death rate of naval soldiers was lower than that of army soldiers.', 'New York citizens in the above statistics include babies, elderly and patients with poor viability, etc.', 'Because the U. S. Navy has a certain strength and fewer casualties during the battle, the enemy forces prefer to attack ordinary citizens who have little resistance.', 'This kind of propaganda by the U. S. Navy is mainly to encourage people to join the army, so it can not help but have exaggerated elements.']