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

B E _ K P C _ H K P _ E H K P_ E H K P

H E D E

Lets check each option one by one :

1) F, E, Q, H ⇒ B,E,F,K,P - C,E,H,K,P - Q,E,H,K,P - H,E,H,K,P

No pattern is followed.

2) F,D,Q,H ⇒ B,E,F,K,P - C,D,H,K,P - Q,E,H,K,P - H,E,H,K,P

No pattern is followed.

3) H,D,Q,E ⇒ B,E,H,K,P - C,D,H,K,P - Q,E,H,K,P - E,E,H,K,P

No pattern is followed.

4) H,E,D,E ⇒ B E H K P /  C E H K P /  D E H K P / E E H K P

In this series, pattern is followed.

 Ans = H E D E