This question is really about tax treaties and how they shape recorded FDI numbers, not about which country has the biggest economy.
Because so much investment, including money from other countries, chose to enter India via Mauritius purely for the tax benefit, Mauritius topped the FDI source list, confirming option (D).
Let's summarize:
So the top source of FDI inflows into India at that time was Mauritius.
In November 2023, which state government declared a fish named “Ghol” as the state fish?