The correct answer is: a) Alluvial soils.
Alluvial soils are the most common type of soil in Coastal Andhra Pradesh. They are formed by the deposition of sediments from rivers and streams. Alluvial soils are typically fertile and well-drained, making them ideal for agriculture.
Black soils are another type of soil found in Coastal Andhra Pradesh. They are formed from the weathering of basalt rocks. Black soils are rich in organic matter and nutrients, making them ideal for growing crops such as rice and cotton.
Red soils are also found in Coastal Andhra Pradesh. They are formed from the weathering of granite rocks. Red soils are less fertile than black soils, but they are well-drained and suitable for growing crops such as millet and sorghum.
Laterite soils are not found in Coastal Andhra Pradesh. They are formed from the weathering of igneous rocks in tropical climates. Laterite soils are highly weathered and leached, making them infertile.
In conclusion, the correct answer is: a) Alluvial soils.