Explanation:

- The Regulating Act of 1773 was a significant legislation enacted by the British Parliament.

- It aimed to address concerns in the administration of the East India Company.

- The Act led to the establishment of the Supreme Court in India.

- The Supreme Court was established in Calcutta in 1774.

- This court had jurisdiction over civil, criminal, admiralty, and ecclesiastical cases.

The options given are:

1. Madras - While an important city, it was not the location of the first Supreme Court under the Regulating Act.

2. Assam - This region was not relevant to the establishment of the Supreme Court in 1774.

3. Calcutta - This is the correct answer.

4. New Delhi - Not applicable since New Delhi became significant later in time.