A series of three-letter groups is given with one term missing. Choose the correct option that completes the sequence: GON, JRQ, MUT, ?

Introduction / Context:
This question examines your ability to recognize patterns in letter sequences. Each term is a three-letter group, and the series progresses according to a fixed rule. Your goal is to identify that rule and then apply it to find the missing group after MUT in the sequence GON, JRQ, MUT, ?.

Given Data / Assumptions:

• Given sequence: GON, JRQ, MUT, ?
• Each term contains three letters.
• The same pattern applies to all three terms provided.
• Alphabet positions: A = 1, B = 2, ..., Z = 26.

Concept / Approach:
We separate the series into three vertical sequences: first letters, second letters and third letters. Then we convert each letter to its numeric position to find how the positions change from one term to the next. If the differences are consistent, we extend each mini-series by one step to obtain the missing group.

Step-by-Step Solution:
Step 1: First letters: G, J, M. Positions: G = 7, J = 10, M = 13. The pattern is +3 each time (7 + 3 = 10, 10 + 3 = 13). Step 2: The next first letter after M is 13 + 3 = 16, which is P. Step 3: Second letters: O, R, U. Positions: O = 15, R = 18, U = 21. Again, each step is +3. Step 4: The next second letter after U is 21 + 3 = 24, which is X. Step 5: Third letters: N, Q, T. Positions: N = 14, Q = 17, T = 20. These also follow a +3 pattern. Step 6: The next third letter after T is 20 + 3 = 23, which is W. Step 7: Combining these results gives P (first position), X (second position) and W (third position), so the missing group is PXW.

Verification / Alternative check:
We can check all four terms in numeric form: GON (7, 15, 14), JRQ (10, 18, 17), MUT (13, 21, 20), PXW (16, 24, 23). In every column, the numbers increase by +3 consistently. This confirms that PXW is the correct continuation of the series.

Why Other Options Are Wrong:
Option A (NOG): The first letter N is 14, which does not follow the +3 pattern from M (13). Option C (JQR): This returns to earlier letters and breaks the strictly increasing pattern in all three positions. Option D (TUM): The letters do not fit the systematic +3 shift across the series.

Common Pitfalls:
One common mistake is to look only at the first letters and ignore the second and third positions. Another is to miscalculate the numeric positions of letters, especially in the middle of the alphabet. The safest method is to write down the positions of all letters and check the pattern in each column separately.

Final Answer:
The term that correctly completes the series is PXW, which is option B.