B. 800, 13%
Feedback S.I. for 1 ½ years = Rs (1164 - 1008) = Rs 156 .
S.I. for 2 years = Rs (156 x 23 x 2)= Rs 208.
Therefore, Principal = Rs (1008 - 208) = Rs 800.
Now, P = 800, T= 2 and S.I. = 208.
Therefore, Rate = (100 x S.I.) / (P x T) = [ (100 x 208)/(800 x 2)]% = 13%