Contour ploughing or Contour Farming or Contour Bunding: ● It is the farming practice of ploughing and/or planting across a slope following its elevation contour lines. So, option 3 is correct. ● These contour lines create a water break which reduces the formation of rills and gullies during times of heavy water run-off; which is a major cause of soil erosion. ● The water break also allows more time for the water to settle into the soil. ● In contour ploughing, the ruts made by the plough run perpendicular rather than parallel to slopes, generally resulting in furrows that curve around the land and are level.