Correct Option: D

Rainfall decreases as winds move westwards up the Ganga Plains. Rajasthan receives very little rain as it lies in the rain-shadow of the Aravali Hills. The climate of Rajasthan varies greatly throughout the state. It is very hot and dry in summer in the desert areas, where dust storms also occur, while it is very cold during the winters. To the west of the Aravali range, the weather is characterized by low rainfall with erratic distribution, extremes of diurnal and annual temperatures, low humidity and high wind velocity. While in the east of the Aravali range, the weather is characterized by relatively low wind velocity and high humidity with better rainfall.