Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series.
X _ U _ B _ O _ Z _ X _ U _ B
1
O Z X U B O Z
2
O Z X U B Z O
3
O X Z U B O Z
4
O Z X B U O Z
Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series.