Which of the following practices can help in water conservation in agriculture ? 1. Reduced or zero tillage of the land 2. Applying gypsum before irrigating the field 3. Allowing crop residue to remain in the field Select the correct answer using the code given below :

Reduced tillage and leaving crop residues (mulching) help conserve water by minimizing soil disturbance, reducing evaporation from the surface, and improving the soil's organic matter and water-holding capacity. Option (d) is the most tempting wrong choice, but gypsum is primarily a chemical soil amendment used to reclaim sodic soils rather than a standard practice for general water conservation. This question tests the core concept of **Conservation Agriculture**, which emphasizes sustainable moisture management through minimal soil mechanical interference and permanent soil cover.