Assertion (A) states that during 2023-24, Singapore emerged as the largest source of FDI to India. According to data released by the Department for Promotion of Industry and Internal Trade (DPIIT), Singapore was indeed the largest source country for FDI equity inflows into India during the financial year 2023-24. Thus, Assertion (A) is true. Reason (R) states that the India Mauritius Tax Treaty amendment has brought a major shift in countries as major sources of FDI to India. The India-Mauritius Double Taxation Avoidance Agreement (DTAA) was amended in 2016 (taking effect from 2017) to withdraw the capital gains tax exemption on investment in Indian shares routed through Mauritius. This significantly reduced the attractiveness of Mauritius as an investment route and led to a shift in FDI inflows towards other jurisdictions like Singapore and the Netherlands. Thus, Reason (R) is true as the amendment did cause a major shift in FDI source countries over time. However, Reason (R) is not the direct and sole explanation for Assertion (A). While the shift away from Mauritius contributed to other countries' increased prominence, including Singapore, it doesn't specifically explain why Singapore became the largest source in 2023-24. Singapore's own economic status, its investment treaty with India, and other factors also contribute to its position. The Reason describes a historical shift, not the specific dynamics that made Singapore the top source in that particular year.