Which of the following pairs is NOT correctly matched?

Ustad Bismillah Khan - Sitar

The correct answer is Option (4) - Ustad Bismillah Khan - Sitar

Pandit Hariprasad Chaurasia - Bamboo flute:  This is a well-known pairing. Pandit Hariprasad Chaurasia is a legendary Indian flutist who is a maestro of the bansuri, a North Indian bamboo flute.

Miyan Tansen - One of the nine jewels:  Miyan Tansen was a renowned musician in Mughal emperor Akbar's court. He was considered one of the nine gems (Navratnas) of Akbar's court, highlighting his exceptional talent.

Ustad Ali Akbar Khan - Sarode: Ustad Ali Akbar Khan was a virtuoso Indian classical musician who played the sarode, a stringed fretted instrument.

Ustad Bismillah Khan - Sitar: Ustad Bismillah Khan was a legendary Indian shehnai player. The shehnai is a double-reed instrument, not a sitar. He was a maestro of the shehnai, a distinct instrument with a powerful and reedy sound. The sitar is another important stringed instrument in Hindustani classical music but different from the shehnai.

Therefore, based on the information above, the incorrect match might be Ustad Bismillah Khan - Sitar  because he is known for playing the shehnai.