Lets do it by finding the L.C.M
(2, 5, 6, 9)
divide the terms by two and leave those which are not divisible
2 (1,5,6,9)
divide the terms by 3 and leave those which are not divisible
2 x 3 (1,5,2,3)
divide the terms by 3 again and leave those which are not divisible
2 x 3 x 3 (1,5,2,1)
divide the terms by two and leave those which are not divisible
2 x 3 x 3 x 2 (1,5,1,1)
divide the terms by five and leave those which are not divisible
2 x 3 x 3 x 2 x 5 (1,1,1,1)
So the L.C.M is :
2 x 3 x 3 x 2 x 5=180
so correct option is D
hope it helps