The correct answer is: a) Alluvial soils.
Alluvial soils are the most fertile soils in Tamil Nadu. They are formed by the deposition of sediments from rivers and streams. These soils are rich in nutrients and are well-drained, making them ideal for growing crops like rice, sugarcane, and bananas.
Black soils are also fertile, but they are not as well-drained as alluvial soils. This can make them prone to waterlogging, which can damage crops.
Red soils are less fertile than alluvial and black soils. They are also more acidic, which can make it difficult for some crops to grow.
Laterite soils are the least fertile soils in Tamil Nadu. They are formed by the weathering of rocks in tropical climates. These soils are low in nutrients and are often acidic.
In conclusion, alluvial soils are the most fertile soils in Tamil Nadu and are ideal for growing crops like rice, sugarcane, and bananas. Black soils are also fertile, but they are not as well-drained as alluvial soils. Red soils are less fertile than alluvial and black soils and are more acidic. Laterite soils are the least fertile soils in Tamil Nadu.