Which statement from the "future potential source #2: wind" article persuades readers to consider the benefits of wind energy because it's already being successfully used elsewhere?       a.  "wind power already has commitments from some of the country's largest companies."      b.  "wind energy comes from harnessing the natural atmospheric heat differentials over the landscape and along coastlines"      c.  "already, multiple countries in europe are using wind energy to meet significant portions of their energy needs"      d.  "consistent investment will bring the wind power industry over the threshold to become a major player in both the energy and job market."