Among the following, which one is the least water-efficient crop?

Sugarcane is the least water-efficient crop because it is a long-duration crop requiring between 1,500 to 2,500 mm of water per cycle, the highest among the given options. While sunflower requires moderate irrigation, it is significantly more water-efficient than sugarcane, and crops like pearl millet and red gram are specifically known for their high drought resistance and low water footprints. The core concept tested here is the relative water-use efficiency and irrigation intensity of major Indian agricultural crops.