The given bar graph shows the sum invested by 4 different persons, A, B, C and D, in a bank on simple interest. Study the graph and answer the question given below.

If the amount received by B after 5 years at rate of interest R% p.a. is equal to the amount received by D after $$3\frac{1}{2}$$ years at the same rate of interest p.a., then the value of R is:

A

9%

B

12%

C

8%

D

10%