Trench method of sugarcane planting is used in

✅ Explanation:
The trench method is also known as the Java method of planting sugarcane. In this method, trenches at a distance of 75 – 90 cm are dug with the help of a ridger or manually to save the cop from lodging.This practice is used mostly in coastal areas where the crops grow very tall and the strong winds during the rainy season cause lodging of canes.

📌 Other Options Explanations:
-(a) North India: North India primarily uses the flat planting method due to its loamy soils and well-drained conditions.
-(b) Western India: Western India also predominantly employs the flat planting method for sugarcane cultivation.
-(d) Waterlogged area: Waterlogged areas are not suitable for sugarcane cultivation as they can lead to root rot and other problems. The trench method is used to avoid waterlogging, not in areas already prone to it.