ISRO 2017-ECE Computational circuits

Question

  The circuit shown in the figure converts

(a) BCD to binary code

(b) Binary to Excess-3 code
(c) Excess-3 to Gray code

(d) Gray to Binary code
 

Answer 1

Take Input 1010 we get 1100 and if input is 0101 then output is 0110. 

Which is Gray to Binary  Here function of And gate is just to increase complexity