Ans. is A
For composition of sets containing pair of elements:
Take first pair from first set say (x1,y1), then pick second element y1 of this pair and check it in the second set of R say (x2,y2). If there is any pair starting with x2=y1, if yes then take its second element y2 and make a subset of (x1,y2) in RoR similarly check for all other pairs from first set.