Explanation:

- Chandipur Sea, situated near Chandipur Beach in Odisha, India, is best known as a missile testing range.

- The Integrated Test Range (ITR), run by DRDO, conducts missile launches here.

- Option 1: Deep sea fishing – While fishing may occur in the general area, Chandipur is not famous for this.

- Option 2: Oil drilling – There is no major oil drilling activity associated with Chandipur Sea.

- Option 3: Missile testing range – Correct! This is what Chandipur is renowned for. It regularly hosts missile tests like Agni, Prithvi, etc.

- Option 4: Overseas communications – Chandipur has no special role in global communications.