The Ponnani port is located at the mouth of which river?

The correct answer is d) Bharathappuzha River.

The Bharathappuzha River, also known as the Nila River, is the longest river in Kerala, India. It is 209 kilometers (130 mi) long and drains an area of 2,860 square kilometers (1,100 sq mi). The river originates in the Western Ghats and flows through the districts of Palakkad, Malappuram, and Thrissur before emptying into the Arabian Sea at Ponnani.

The Bharathappuzha River is an important source of water for irrigation, drinking water, and hydroelectric power. It is also a popular tourist destination, known for its scenic beauty and backwaters.

The other options are incorrect because:

• The Kuttiyadi River is a tributary of the Bharathappuzha River.
• The Chaliyar River is a tributary of the Periyar River.
• The Periyar River is a river in Kerala and Tamil Nadu, India. It is 244 kilometers (152 mi) long and drains an area of 5,600 square kilometers (2,160 sq mi). The river originates in the Western Ghats and flows through the districts of Idukki, Ernakulam, Thrissur, Palakkad, and Malappuram before emptying into the Arabian Sea at Azhikkal.