**Explanation:**

The correct answer is option A, Ottan Thullal.

**Ottan Thullal: A Solo Dance**

Ottan Thullal is a classical solo dance form that originated in the southern Indian state of Kerala. It is a highly expressive dance form that combines elements of dance, drama, and poetry. Ottan Thullal is performed by a single performer, making it a solo dance.

**Other Dance Forms:**

a) Kuchipudi: Kuchipudi is a classical dance form that originated in the Indian state of Andhra Pradesh. It is known for its graceful movements and intricate footwork. However, Kuchipudi is primarily performed as a solo dance, but it can also be performed in groups or ensembles.

b) Yakshagana: Yakshagana is a traditional dance-drama form from the coastal regions of Karnataka, India. It is characterized by vibrant costumes, elaborate makeup, and vigorous dance movements. Yakshagana is usually performed by a group of dancers, including actors, musicians, and singers, rather than as a solo dance.

c) Odissi: Odissi is one of the eight classical dance forms of India and originated in the state of Odisha. It is known for its fluid movements, intricate footwork, and expressive storytelling. Odissi can be performed as a solo dance, duet, or group performance, depending on the composition and choreography.

**Conclusion:**

In conclusion, among the given options, Ottan Thullal is the only dance form that is performed as a solo dance. Kuchipudi, Yakshagana, and Odissi can also be performed as solo dances, but they are not exclusively solo dance forms.