The correct answer is a) Pamba River.
Pamba River is a river in Kerala, India. It is the largest tributary of the Achankovil River. The river is 120 kilometers long and originates in the Western Ghats. It flows through the districts of Pathanamthitta, Alappuzha, and Kottayam. The river is a major source of irrigation and drinking water for the people of Kerala. It is also a popular tourist destination.
Vallamkali is a traditional boat race that is held on the Pamba River. The race is held every year during the Onam festival. The race is a competition between teams of oarsmen who row their boats along the river. The race is a popular event and attracts a large number of spectators.
The other options are incorrect because they are not associated with the traditional boat race called Vallamkali.
b) Periyar River is a river in Kerala, India. It is the longest river in the state. The river is 244 kilometers long and originates in the Western Ghats. It flows through the districts of Idukki, Ernakulam, Thrissur, Palakkad, and Malappuram. The river is a major source of irrigation and drinking water for the people of Kerala. It is also a popular tourist destination.
c) Kabini River is a river in Karnataka, India. It is a tributary of the Kaveri River. The river is 290 kilometers long and originates in the Western Ghats. It flows through the districts of Mysore, Chamarajanagar, and Hassan. The river is a major source of irrigation and drinking water for the people of Karnataka. It is also a popular tourist destination.
d) Chaliyar River is a river in Kerala, India. It is a tributary of the Pamba River. The river is 100 kilometers long and originates in the Western Ghats. It flows through the districts of Palakkad and Malappuram. The river is a major source of irrigation and drinking water for the people of Kerala. It is also a popular tourist destination.