(a) It is expected to harness wind power to minimum in open space

(b) The potential energy content of wind blowing at high altitudes is the source of wind power

(c) Wind hitting at the blades of a windmill causes them to rotate The rotation thus achieved can be utilised further

(d) One possible method of utilising the energy of rotational motion of the blades of a windmill is to run the turbine of an electric generator

Answer: (b) The potential energy content of wind blowing at high altitudes is the source of wind power.

Reason: Potential energy content of wind blowing at high altitudes is more responsible for the power produced by the wind.