Explanation:

- Option 1: Ghazal

- Correct Answer: Jagjit Singh is most famously known for his contribution to the Ghazal genre. His soulful renditions and compositions have brought Ghazals to a wider audience, making them popular across generations.

- Option 2: Bhajan

- While Jagjit Singh did sing some Bhajans, he is not primarily renowned for this genre.

- Option 3: Carnatic Music

- Carnatic music is a classical music form from South India. Jagjit Singh, being a singer of Ghazals, is not associated with this style.

- Option 4: Hindustani Music

- Hindustani music is the classical music of Northern India. Although Jagjit Singh's music, especially Ghazals, is influenced by Hindustani music, this is not his primary genre.

The primary genre associated with Jagjit Singh is Ghazal, making Option 1 the correct answer.