Which is a geometric sequence 6, 18, 54, 162 or 3, 6, 9, 12, 15 or 1, 4, 5, 9, 14 or 3, 5, 8, 13, 21

Basically for geometric sequence
an times r=a_(n+1)
see

6*3=18
18*3=54
54*3=162
yes

3*2=6
6*2=12, it says 9 but should be 12
not a geometric

1*4=4
4*4=16, nope, it says next term is 5,

3*5/3=5
5*5/3=25/3, nope, says next term is 8

geometric sequense is first one
6,18,54,162

Understanding what? lol