Answer: Third and Fourth options are correct.
Step-by-step explanation:
Since we have given that
L.C.M. should be 18.
As we know that
Least common multiple of 2 and 6 is 6
Least common multiple of 3 and 6 is 6
Least common multiple of 2 and 9 is 18
Least common multiple of 9 and 6 is 18
Least common multiple of 12 and 6 is 12
Hence, Third and Fourth options are correct.