Explanation:

- Option 1: Agra Gharana

- Originated from the Dhrupad tradition.

- Known for powerful and clear intonation.

- Focuses on a blend of Dhrupad and Khayal styles.

- Option 2: Kirana Gharana

- Emphasizes on melodic and emotional expression.

- Notable for its slow-tempo renditions.

- Option 3: Atrauli Gharana

- Founded by Alladiya Khan in the late 19th century.

- Known for intricate ragas and complex compositions.

- Option 4: Gwalior Gharana

- Correct Answer: It is the oldest Khayal Gharana.

- Dates back to the Mughal era, around the 16th century.

- Known for its clarity, structure, and emphasis on Tansen’s music lineage.

The Gwalior Gharana holds historical significance for its foundational role in the Khayal tradition, setting the form and style widely followed and adapted by other gharanas.