Explanation: The coastal plains of Karnataka are an important geographical feature of the state, forming part of the larger western coastal region of India. This region is characterized by its low-lying areas that extend from the Arabian Sea inland, providing fertile land for agriculture and supporting a variety of ecosystems.
The coastal plains of Karnataka can be divided into several distinct regions, each with its own unique characteristics. The most significant of these regions, in the context of this question, are the Malabar, Konkan, Kannad, and Northern Circar plains.
1. **Malabar Coast**: This coastal region is located in the state of Kerala, which is south of Karnataka. The Malabar coast is known for its historical significance in the spice trade and its lush green landscapes. It is not directly south of Goa, which is why it is not the correct answer.
2. **Konkan Coast**: The Konkan coast is located in the western part of India, primarily in the state of Maharashtra, but it extends into the northern part of Karnataka. It is known for its scenic beauty and is not directly south of Goa, making it an incorrect option.
3. **Kannad Coastal Plain**: This is the correct answer. The Kannad coastal plain is located in the southern part of Karnataka and lies directly south of Goa. It is part of the larger coastal region of Karnataka and is characterized by its fertile soil and agricultural productivity. The Kannad region is distinct from the Malabar and Konkan coasts, each of which has its own unique geographical and cultural features.
4. **Northern Circar**: This is a historical region located in the northeastern part of Andhra Pradesh, far from the western coast of India. It is not related to the coastal plains of Karnataka and is therefore an incorrect option.
Understanding the geographical layout of the coastal regions in Karnataka is crucial for comprehending the state's geography and its role in the broader context of the western coast of India. The Kannad coastal plain, being directly south of Goa, is a significant part of Karnataka's coastal geography and plays a vital role in the state's economic and ecological landscape.