Which of these sequences is geometric?
2,4,6,82, 4, 6, 82,4,6,8
1,3,9,271, 3, 9, 271,3,9,27
1,2,4,81, 2, 4, 81,2,4,8
1,4,9,161, 4, 9, 161,4,9,16