Select the option that represents the letters that, when sequentially placed from left to right in the following blanks, will complete the letter-series.P_ SH_BK_HPB_S_PB _H

The given series is: P _ _ S H _ B K _ H P B _ S _ P B _ _ HLet's count the total number of spaces and letters: there are 20 positions in total. We can divide the pattern into 4 groups of 5 letters each:P _ _ S H | _ B K _ H | P B _ S _ | P B _ _ HComparing the groups:The first letters of the groups are: $\text{P, \_, P, P}\to$ suggests the first letter is always $\text{P}$.The second letters are: $\text{\_, B, B, B}\to$ suggests the second letter is always $\text{B}$.The third letters are: $\text{\_, K, \_, \_}\to$ suggests the third letter is always $\text{K}$.The fourth letters are: $\text{S, \_, S, \_}\to$ suggests the fourth letter is always $\text{S}$.The fifth letters are: $\text{H, H, \_, H}\to$ suggests the fifth letter is always $\text{H}$.Thus, the repeating pattern group is P B K S H.Let's fill in the blanks according to this repeating pattern:Group 1: $\text{P [B] [K] S H}$ Group 2: $\text{[P] B K [S] H}$ Group 3: $\text{P B [K] S [H]}$ Group 4: $\text{P B [K] [S] H}$ The sequence of letters inserted in the blanks is: B, K, P, S, K, H, K, S.