Answer : Option A)
Since carry need to be generated for when sum > 2 (ternary).
Condition for Carry to be set: Inputs =2+1 or 1+2 or 2+2 or 1+1(+1 by Carry in) BUT not required as it is given 0.
i.e in binary : (x1,x0:y1,y0)= (1,0:0,1) or (0,1:1,0) or (1,0:1,0)
Hence on Solving by K-map:
Hence ,answer A.