Essayist: If Earth' s population continues to grow geometrically, then in a few centuries there will be ten people for every square meter (approximately one person per square foot) of Earth' s surface. Some people have claimed that this will probably not be a problem, since humans will have learned by then how to colonize other planets. This would, however, be a temporary solution at best: if the population continues to double every 30 years, and if in the year 2500 half of Earth' s population emigrated to Mars, then by the year 2530 Earth would be just as crowded as it had been before the emigration. Which one of the following most accurately expresses the conclusion drawn in the essayist's argument? ['Learning how to colonize other planets would, at best, be a temporary solution to the overcrowding of Earth.', "The population of Earth's surface will probably continue to grow geometrically even if temporary solutions to population growth, such as colonizing other planets, are adopted.", "If Earth's population continues to grow geometrically, then in a few centuries the population density of Earth's surface will be ten people per square meter.", "Due to the continuing geometric growth of Earth's population, the problem of overpopulation of Earth will probably persist."]