Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series.
Q _ L _ P Q P _ B P Q _ L B _ Q _ L _ P
1
P, B, L, P, P, P, B
2
P, P, P, B, B, L, Q
3
P, Q, P, L, P, B, P
4
P, Q, L, P, B, P, B