Digital-Full Substractor

Question

Answer 1

difference in full substracor is same as addition in full adder and that is sop of {1,2,4,7}.

Lets solve the option C.

First mux gives x'y' + xy as output. and this is input for next mux.

 Evaluation = ( x'y' + xy)' z' +  ( x'y + xy')z

                  = (x'y + xy')z'  +  ( x'y + xy')z   

                  = x'yz' + xy'z'  +  x'yz + xy'z

                  =sop {1,2,4,7}

So C. should be ans

Comments

Once please check A..i think it would be A too