The correct option is A Mauritius
Mauritius was the largest source of Foreign Direct Investment (FDI) in India in FY17, according to recent census by the Reserve Bank of India (RBI). It had 21.8% share at market value. As per RBIs data on Census on Foreign Liabilities and Assets of Indian Direct Investment Companies 2016-17, United States had acquired 2nd position followed by UK, Singapore and Japan. Beside this, Singapore (19.7% was the major FDI destination, followed by the Netherlands, Mauritius, and the USA. According to the data, the manufacturing sector accounted for nearly half of the total FDI at market prices. Information and communication services, and financial and insurance activities were the other major sectors that attracted FDI.