Answer : 4. "Maharashtra"
Explanation :

Answer: D) Maharashtra Explanation: The three state-run Oil Marketing Companies (OMCs) – Indian Oil Corporation (IOC), Hindustan Petroleum Corp Ltd (HPCL) and Bharat Petroleum Corp Ltd (BPCL) have signed an agreement to jointly set up the world’s largest refinery and petrochemical complex at Ratnagiri district of Maharashtra at a cost of $40 billion. The IOC will hold 50% stake and HPCL & BPCL will will take 25% stake each in the new complex. The refinery will produce petrol, diesel, LPG, ATF and feedstock for making petrochemical that are basic building blocks in plastic, chemical and textile industries. The refinery is expected to be completed by 2022.