Three of the following four triads are alike in a certain way as they are formed by performing same mathematical operations among themselves and thus form a group.
Which triad does NOT belong to that group?
1
2 ∶ 5 ∶ 8
2
5 ∶ 10 ∶ 125
3
12 ∶ 25 ∶ 1728
4
3 ∶ 7 ∶ 27