Explanation:

Option ‘b’ is incorrect because the flooding method of irrigation generally practiced in states of Haryana, Punjab , western UP etc. is one of the major reasons for rising salinity of soil in these regions.
Owing to cheap electricity and availability of water coupled with lack of know-how, farmers tend to flood their fields with irrigation waters. Excess water seeps to ground and then rises to surface due to capillary action. During this process it brings salts to the surface which accumulate on top layer and make soil saline.