The correct answer is option 3, Mangalore.
First, let`s understand what is being exported. Iron ore from the Kudremukh mines is what is being referred to here.
Now, let`s analyze each option:
- Option 1, Marmugao: Marmugao is a major port in Goa, but it is not known for iron ore exports.
- Option 2, Cochin: Cochin is another major port in Kerala, but it is not known for iron ore exports.
- Option 3, Mangalore: Mangalore is a port city in Karnataka and it is well-known for its iron ore exports. So, this option is correct.
- Option 4, Chennai: Chennai is a major port in Tamil Nadu, but it is not known for iron ore exports.
Therefore, the correct answer is option 3, Mangalore.