The correct option is Nilgiri hills.
Explanation
The Peninsular Plateau of India is bordered by the Western Ghats on the west and the Eastern Ghats on the east. While the Western Ghats form a continuous wall, the Eastern Ghats are discontinuous and dissected by rivers flowing into the Bay of Bengal. These two major mountain systems converge at a specific structural knot in the southern part of the peninsula.
Detailed Analysis:
- Nilgiri Hills: The Eastern Ghats and the Western Ghats meet at the Nilgiri Hills. This range acts as a connecting link between the two ghats. The Nilgiris are a block mountain structure located at the tri-junction of Karnataka, Kerala, and Tamil Nadu.
- Anaimalai Hills: These are located to the south of the Nilgiri Hills, separated by the Palghat Gap. They are part of the Western Ghats but are not the meeting point of the two ranges.
- Cardamom Hills: These constitute the southernmost part of the Western Ghats, located further south of the Anaimalai Hills.
- Palani Hills: These are an eastward extension of the Western Ghats, branching off from the Anaimalai range, rather than the convergence point of the Eastern and Western Ghats.
Key Takeaway:
The Nilgiri Hills serve as the geographical knot where the Eastern Ghats join the Western Ghats, marking the transition to the southern hill complex of the Peninsular India.