Two sums are in the ratio 4:3. Both the sums are lent at 5% per annum and 10% per annum under compound interest for two years. The difference between the interest at the end of two years is Rs. 1540. What was the sum lent at 10% per annum?

• A. Rs 16000
• B. Rs 21000
• C. Rs 15000
• D. Rs 28000