A sum was invested at a certain rate of simple interest per annum for 8 years. Had it been invested at a rate of simple interest per annum that is 8% higher than the rate at which the sum had been actually invested, it would have fetched ₹4,000 more as interest at the end of the 8-year period. What was the sum invested?
A6,925
B6,500
C6,250
D6,750