Explanation:

- Vikku Vinayakaram is renowned for his exceptional skill in playing the Ghatam, a traditional Indian percussion instrument.

- The Ghatam is a clay pot instrument, often used in Carnatic music, known for its unique sound and technique.

- The Pakhawaj is another Indian percussion instrument, but it is a barrel-shaped drum and not associated with Vikku Vinayakaram.

- The Dholak is a two-headed hand drum, commonly used in folk and traditional music, but not linked to Vikku Vinayakaram.

- The Tabla is a pair of drums widely used in Indian classical music but not played by Vikku Vinayakaram.

Option 4: Ghatam is the correct answer.