C
Wind farms, which generate electricity using arrays of thousands of wind-powered turbines, require vast expanses of open land. County X and County Y have similar terrain, but the population density of County X is significantly higher than that of County Y. Ttherefore, a wind farm proposed for one of the two counties should be built in County Y rather than in County X. Which of the following, if true, most seriously weakens the planner's argument?
A: Some of the electricity generated by wind farms in County Y would be purchased by users outside the county.
B: Wind farms require more land per unit of electricity generated than does any other type of electrical-generation facility.
C: Nearly all of County X's population is concentrated in a small part of the county, while County Y's population is spread evenly throughout the country.
D: County X and County Y are adjacent to each other, and both are located in the windiest area of the state.