Explanation:

- Ustad Allauddin Khan was a legendary sarod player and composer.

- He is best known for shaping and popularizing the Maihar Gharana in Hindustani classical music, Option 3: Maihar.

- The Maihar Gharana was named after the princely state of Maihar where Khan served as a court musician.

- Option 1: Kasur-Patiala Gharana is more associated with vocalists, particularly in the realm of classical Khayal singing.

- Option 2: Benaras is well known for tabla players and classical vocalists, not typically associated with sarod players.

- Option 4: Rangeela is not traditionally known as a gharana in the context of Indian classical music.