Select the option that represents the letters that when sequentially placed in the blanks below will complete the letter series.
S _ P _ _ G _ I S G _ I _ _ P I

Select the combination of letters that when sequentially placed from left to right in the blanks of the given series will complete the letter series. 

A _ _ O U A E I _ _A _ I _ U A E _ O _

Select the combination of letters that when sequentially placed in the blanks of the given series, will complete the series. 

_yz_zx_xyx_z_zxzx_

Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series.

U K _ _ Z U _ T M _ U K _ M Z _ K T _ Z

Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series.

TK _ TKT_ P_ K _  KPTK _  K _ TK

Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series.

H Y _ R _ H Y _ R B _ Y U _B H _ U _ B

Which letter will replace the question mark (?) in the following series?

J, L, P, V, D, N, ?

Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series.

G _ C T _ X _ T G X _ T _ X C T G _ C T

Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series.

Q _ P _ M _ A _ T _ Q A _ T M

Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series.

r _ x l _ q _ _ x _ p q _ e _ l p _

Select the letter-cluster from among the given options that can replace the question mark (?) in the following series.

BKR, DNV, FQZ, ?, JWH