The ship building yard Mazgaon Dock is situated at :

Vishakhapatnam
Cochin
Kolkata
Mumbai

The correct answer is (d) Mumbai.

Mazgaon Dock is a shipyard located in Mumbai, India. It is one of the oldest and largest shipyards in India. The shipyard was established in 1839 by the British East India Company. It was originally known as the Bombay Dockyard. The shipyard was renamed Mazgaon Dock in 1914.

Mazgaon Dock has a long history of building ships for the Indian Navy and the Indian Merchant Navy. The shipyard has also built ships for foreign customers. In recent years, the shipyard has focused on building commercial ships, such as tankers and bulk carriers.

Mazgaon Dock is a major employer in Mumbai. The shipyard employs over 10,000 people. The shipyard is also a major contributor to the Indian economy.

The other options are incorrect.

(a) Vishakhapatnam is a city in Andhra Pradesh, India. It is the headquarters of the Indian Navy’s Eastern Naval Command. Vishakhapatnam does not have a shipyard.

(b) Cochin is a city in Kerala, India. It is a major port city in India. Cochin does not have a shipyard.

(c) Kolkata is a city in West Bengal, India. It is the former capital of India. Kolkata does not have a shipyard.