Your answer would be D. You can find the neutrons by subtracting the mass by the atomic number. 14-6=8 neutrons.
Two things that INCREASE population, would be an increase in leisure space. Another is if the area is sustainable for life. Two things that would DECREASE population, would be a scarcity of any required resources. A decrease in space, and not a sustainable area.
I would say Diandra, because she provides the most in depth description!