The festival celebrated with boat races, a major attraction in Kerala, also observed in parts of Karnataka:

Onam
Varamahalakshmi
Karaga
Kambala

The correct answer is: D) Kambala.

Kambala is a buffalo race held in the coastal districts of Karnataka and Kerala. It is a major attraction in Kerala, also observed in parts of Karnataka. The race is held in a paddy field filled with water and is a test of the strength and stamina of the buffaloes and the skill of the boatmen.

Onam is a harvest festival celebrated in Kerala. It is a major tourist attraction and is celebrated with a variety of cultural events and activities.

Varamahalakshmi is a Hindu festival celebrated in honor of Lakshmi, the goddess of wealth. It is celebrated in the month of October or November.

Karaga is a Tamil festival celebrated in honor of the goddess Draupadi. It is celebrated in the month of April or May.