A.
{(1,2),(1,3)),(1,6),(1,12),(2,4),(2,6),(3,6),(3,12),(6,12) }
B.
{(1,2),(1,3),(1,4),(1,6),(2,4),(2,6),(3,6),(3,12),(6,12) }
C.
{(1,2),(1,3),(2,4),(2,6),(3,6),(4,12),(6,12)}
D.
{(1,2),(1,3),(1,4),(1,6),(1,12),(2,4),(2,6),(2,12),(3,6),(3,12),(4,12),(6,12),(12,12) }