The correct answer is c) Idukki.
Graphite is a mineral that is used in a variety of products, including pencils, lubricants, and batteries. It is found in many parts of the world, including India. The largest deposits of graphite in India are located in the state of Jharkhand. However, there are also significant deposits of graphite in the state of Kerala, particularly in the district of Idukki.
The graphite deposits in Idukki are located in the Western Ghats mountain range. The graphite is found in metamorphic rocks that were formed when ancient sediments were subjected to heat and pressure. The graphite is mined from open-pit mines.
The graphite from Idukki is high quality and is used in a variety of products, including pencils, lubricants, and batteries. The graphite industry in Idukki is an important part of the local economy.
The other options are incorrect because they do not have significant deposits of graphite.
a) Wayanad is a district in the state of Kerala. It is located in the Western Ghats mountain range. The district is known for its coffee plantations and its natural beauty. However, there are no significant deposits of graphite in Wayanad.
b) Kottayam is a district in the state of Kerala. It is located in the central part of the state. The district is known for its tea plantations and its backwaters. However, there are no significant deposits of graphite in Kottayam.
d) Ernakulam is a district in the state of Kerala. It is located on the Arabian Sea coast. The district is known for its commercial and industrial activity. However, there are no significant deposits of graphite in Ernakulam.