(a) afforestation

(b) thermal power plants

(c) loss of forest, and decreased rainfall

(d) cropping of high water demanding crops

Correct option – ( b )

Explanation – ground water will not  deplete because of thermal power plants . This is so because thermal power plants have no connection with ground water . Afforestation destruction of seepage , crops demanding high water content decreases the level of water underground . If the rainfall is reduced it affects the underground level of water .