Determine the transformer tap ratios when the receiving end voltage is equal to the sending end voltage, the high voltage line operates at 220 kV and transmit 80 MW at 0.8 pf and the impedance of the line is (40+j140)ohm. Assume tstr=1.0

(A) 0.8 (B) 0.9 (C) 0.7 (D) 0.6