Which of the following is a geometric sequence?
5,10,20,40,…5, 10, 20, 40, \ldots5,10,20,40,…
1,4,9,16,…1, 4, 9, 16, \ldots1,4,9,16,…
3,6,9,12,…3, 6, 9, 12, \ldots3,6,9,12,…
2,5,8,11,…2, 5, 8, 11, \ldots2,5,8,11,…