The correct answer is option 3, Himachal Pradesh.

Contour bunding and contour ploughing are agricultural practices used to prevent soil erosion on sloping lands. Contour bunding involves constructing a series of small ridges along the contour lines of the land to slow down the flow of water and prevent soil erosion. Contour ploughing, on the other hand, involves ploughing the land perpendicular to the slope, again to prevent soil erosion.

Himachal Pradesh is a state in northern India known for its mountainous terrain and hilly landscapes. This makes it a suitable region for the implementation of contour bunding and contour ploughing techniques. By using these practices, farmers in Himachal Pradesh can effectively manage soil erosion and improve soil fertility, which is important for agricultural productivity in the region.

While Punjab, Haryana, and Rajasthan are also agricultural states in India, they are known for their flat landscapes and extensive use of irrigation techniques. Therefore, they may not be the most suitable candidates for contour bunding and contour ploughing practices.