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

Question

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

C G K, G K O, K O S, O S W, ?

1. A. SDA
2. B. KNB
3. C. SWA (Correct answer)
4. D. KJH

Correct Answer

Option C — SWA

Detailed Solution & Explanation

The correct answer is SWA.

Key Points

• Each group is built from a +4 letter step.
• Reading C-G-K, G-K-O, K-O-S, O-S-W, every group takes the last two letters of the previous group and appends the next letter four places ahead.
• After O-S-W, carry forward S and W, then W + 4 = A (wrapping past Z), giving S W A.
• Convert letters to positions and track the overlap-and-add rule rather than eyeballing; the alphabet wrap (W→A) is the step the wrong options miss.