**Correct option (A) 13% **

**Explanation:**

P + SI for 3.5 yrs = Rs. 873

P + SI for 2 yrs = Rs 756

On subtracting, SI for 1.5 yrs = Rs. 117

Therefore, SI for 2 yrs = (Rs 117/1.5 x 2) = Rs.156

P = 756 – 156 = Rs, 600

and rate = (100 x 156/600 x 2) = 13% per annum