Explanation

This tests compound interest with sub-annual compounding. At 10% compounded half-yearly, each half-year earns 5%, and there are 2 half-years in the year: amount = 10000(1.05)² = 11025. Interest = 11025 - 10000 = ₹1025. Option (a) ₹1000 is the simple-interest trap — compounding half-yearly earns slightly more than the nominal 10%. Hence option (b).