Select the option that represents the letters that, when sequentially placed from left to right in the following blanks, will complete the letter series.
_ K _ I W _ J _ W _ _ I _ K J _

Let's count the total number of characters including spaces: there are 16 slots.
Let's divide this series into 4 equal blocks of 4 letters each:
_ K _ I | W _ J _ | W _ _ I | _ K J _

Let's deduce the repeating block pattern:
Comparing Block 2 (W _ J _) and Block 4 (_ K J _), we notice they share J at the third position. We can deduce a general block structure: W K J I.

Let's verify by filling W K J I into all blocks:

Block 1: W K J I (Blanks filled: W, J)

Block 2: W K J I (Blanks filled: K, I)

Block 3: W K J I (Blanks filled: K, J)

Block 4: W K J I (Blanks filled: W, I)

The filled elements in sequence are: W, J, K, I, K, J, W, I
This matches Option B perfectly.