The correct answer is (d) Periyar.
The Periyar is a river in the Indian state of Kerala. It is the longest river in Kerala, and the third longest river in the Western Ghats. The river originates in the Western Ghats near the town of Thekkady, and flows through the districts of Idukki, Ernakulam, Thrissur, Palakkad, and Malappuram. The Periyar joins the Arabian Sea near the town of Valiyathura.
The Periyar is a major source of water for irrigation, drinking water, and hydroelectric power in Kerala. The river is also a popular tourist destination, and is home to a number of wildlife sanctuaries, including the Periyar Tiger Reserve.
The other options are incorrect because they are not rivers in Kerala. The Kaveri is a river in the Indian states of Karnataka, Tamil Nadu, and Puducherry. The Krishna is a river in the Indian states of Andhra Pradesh, Telangana, Karnataka, and Maharashtra. The Godavari is a river in the Indian states of Andhra Pradesh, Telangana, Maharashtra, Chhattisgarh, Madhya Pradesh, and Odisha.