A lent 5000 Rs. to B for 2 years and 3000 Rs. to C for 4 years on simple interest at the same rate of interest and received 2200 Rs. in all from both as interest. The rate of interest per annum is :
[A] $7\frac{1}{8}\%$
[B] 10%
[C] 7%
[D] 5%