Figure below shows D type Flip-Flops connected as shift register, then outputs Q_D, Q_C, Q_B, Q_A are given by:

1. 
2. 
3. 

Here D_A = Q_D ⊕ Q_C; D_B = Q_A; D_C = Q_B; D_D = Q_C For the given input string, outputs are Q_D, Q_C, Q_B, Q_A. Therefore right most bit is Q_A and left most bit is Q_D. Now we determine the string sequence according to the above mentioned equations. (i) (ii) (iii)