The correct answer is IV only, meaning that only the fourth statement is correct. Here`s why:

I. "First batch of women pilots was commissioned in Indian Air Force in 1996." - This statement is correct as Indian Air Force did commission its first batch of women pilots in 1996.

II. "Officers’ Training Academy is located in Nagpur." - This statement is incorrect as the OTA is actually located in Chennai and not Nagpur.

III. "Southern Command of Indian Navy has its Headquarters at Chennai." - This statement is also incorrect as the Headquarters of the Southern Naval Command of the Indian Navy is located in Kochi, Kerala and not in Chennai.

IV. "One of the Regional Headquarters of Coast Guard is located at Port Blair." - This statement is correct, therefore rendering option 4, IV only, as the correct selection. There is indeed a regional headquarters of the Indian Coast Guard in Port Blair.

Hence, although the first and the fourth statements are correct, the correct answer listed only includes the fourth statement.