Step 1: Understanding Naharkatia oil field.
Naharkatia is one of the oldest oil fields in India, located in the northeastern region.
Step 2: Correct location.
It lies in Arunachal Pradesh and is part of India’s petroleum exploration zones.
Step 3: Analyzing the options.
(A) Arunachal Pradesh: Correct — location of Naharkatia.
(B) Assam: Incorrect, though Assam has many oil fields like Digboi.
(C) Nagaland: Incorrect.
(D) Tripura: Incorrect.
Step 4: Conclusion.
The correct answer is (A) Arunachal Pradesh.