A certain sum is divided between A, B, C and D such that the ratio of the shares of A and B is 3 ∶ 4, that of B and C is 5 ∶ 6 and that of C and D is 9 ∶ 10. If the difference between the shares of A and C is Rs.3,240, then what is the share of D?

1. Rs.9,520

2. Rs.8,800

3. Rs.8,640

4. Rs.9,600