What conclusions can be made about the series ∞ 2 cos (πn) n n = 1 and the integral test?

A group of environmentalists were discussing the benefits and drawbacks associated with using fossil fuels. Which argument best fits the conversation?

Fossil fuels are cheaper than alternative forms of energy. Fossil fuel reserves will never be depleted. Fossil fuels are easily renewed. Fossil fuel use does not affect the environment.