Explanation:

- Pandit Shiv Kumar Sharma was a legendary Indian musician known for bringing the santoor to prominence on the global stage.

- Option 1: Piano is a keyboard instrument and is not typically associated with Indian classical music legends like Shiv Kumar Sharma.

- Option 2: Sarod is a stringed instrument used in Indian classical music, popularized by musicians like Ustad Amjad Ali Khan, but not associated with Shiv Kumar Sharma.

- Option 3: Harmonica is primarily a Western instrument and not relevant to Pandit Shiv Kumar Sharma's work or Indian classical music.

- Option 4: Santoor is the correct choice. It’s an Indian hammered dulcimer and Pandit Shiv Kumar Sharma was celebrated for his virtuosity with this instrument.

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