The correct answer is: a) Maize
Maize is a cereal crop that is grown in many parts of the world. It is a major food source for humans and animals, and it is also used to make a variety of products, such as cornmeal, cornstarch, and ethanol. Maize is a relatively drought-tolerant crop, and it can be grown on a variety of soils, including sandy soils.
Mustard is a cruciferous vegetable that is grown for its seeds, which are used to make mustard oil and mustard flour. Mustard is a cool-season crop, and it is typically grown in the spring or fall. Mustard can be grown on a variety of soils, but it prefers well-drained soils.
Sugarcane is a grass that is grown for its sugar-rich juice. Sugarcane is a tropical crop, and it is typically grown in warm, humid climates. Sugarcane can be grown on a variety of soils, but it prefers well-drained soils.
Groundnut, also known as peanut, is a legume that is grown for its edible seeds. Groundnut is a warm-season crop, and it is typically grown in tropical and subtropical climates. Groundnut can be grown on a variety of soils, but it prefers well-drained soils.
In southwestern Punjab, the sandy soils are not suitable for growing sugarcane, mustard, or groundnut. Maize, on the other hand, is a drought-tolerant crop that can be grown on sandy soils. Therefore, the correct answer is: a) Maize.