**A. RS. 698**

B. RS. 700

C. RS. 523

D. RS. 600

**Solution:**

\[\left. \begin{array} { l } { \text { S.I. for } 1 \text { year } = \text { Rs. } ( 854 – 815 ) = \text { Rs. } 39 } \\ { \text { S.I. for } 3 \text { years } = Rs. ( 39 \times 3 ) = Rs \text { . } 117 \text { . } } \\ { \therefore \text { Principal } = Rs \text { . } ( 815 – 117 ) = Rs .698 } \end{array} \right.\]