India's external debt increased from US $98,158 million as at the end of March 2000 to US $100,225 million as at the end of March 2001 due to increase in

1. The question states that India's external debt increased from US \$98,158 million at end March 2000 to US \$100,225 million at end March 2001. 2. This represents an increase of US \$2,067 million over the year. 3. External debt comprises various components including multilateral debt (from institutions like World Bank, ADB), bilateral debt (from individual countries), commercial borrowings, NRI deposits, rupee debt, and short-term debt. 4. According to Reserve Bank of India data for that period (FY 2000-01), the increase in India's external debt was primarily driven by increases in multilateral and bilateral debt components, as well as commercial borrowings. However, looking at the options provided and typical drivers, government borrowings often contribute significantly. 5. Option A (multilateral and bilateral debt) represents loans typically taken by the government or government-backed entities from international institutions and foreign governments. An increase in these would directly increase the external debt stock. The provided answer 'a' indicates this was considered the primary driver for the overall increase in that specific year amongst the choices given.