The correct answer is: a) Double or multiple cropping.
Double or multiple cropping is the practice of growing two or more crops in the same field in the same year. This is often done in areas with assured irrigation, as it allows farmers to take advantage of the available water to produce more food.
Shifting cultivation is a type of agriculture in which land is cleared and used for a short period of time, then abandoned and allowed to return to forest. This is often done in areas with low rainfall, as it allows the land to recover its nutrients.
Dryland farming is a type of agriculture that is practiced in areas with low rainfall. Farmers in dryland areas often use techniques such as terracing and irrigation to conserve water.
Horticulture is the practice of growing fruits, vegetables, and other plants for food or ornamental purposes. It is often done in areas with a Mediterranean climate, which has warm, dry summers and cool, wet winters.
In conclusion, areas with assured irrigation often practice double or multiple cropping. This is because it allows farmers to take advantage of the available water to produce more food.