A certain sum amounts to ₹12,740 in 4 years and to ₹15,925 in $$7\frac{7}{2}$$ years at the same rate percentage per annum at simple interest. The sum (in ₹) and the rate percentage per annum, respectively, are:

A

₹7,800; 10

B

₹9,100; 10

C

₹7,800; 7.5

D

₹9,100; 7.5