combinational logic circuit

Question

consider two 4-bit numbers A=A3 A2 A1 A0 and B=B3 B2 B1 B0 and the expression x=AiBi+AiBi for  i=0,1,2,3. the expression A3B3+x3A2B2+x3x2A1B1+x3x2x1A0B0 evaluates to 1 if

a- A=b

b-A!=b

c-A>B

d-A<B

Comments

What does + mean  OR or Binary sum?

1 + 1 = 1 ( + means OR)

1 + 1 = 10 ( binary sum)

Answer 1

Ans is c as after putting xi values in expression if uh look closely if a>b then ab bar will hold 1observe closely