In the letter series EJO, TYD, INS, XCH, ?, find the missing three-letter term.

Introduction / Context:
This letter series question involves cyclic movement through the alphabet. Each term has three letters, and the pattern often applies separately to each position. Some movements wrap around from Z to A, so thinking in terms of positions on a circular alphabet is helpful.

Given Data / Assumptions:

• Series: EJO, TYD, INS, XCH, ?
• Exactly one three letter group is missing.
• The rule is expected to be consistent for each column of letters.

Concept / Approach:
We convert each letter into its alphabet position and then check how the first letters change among themselves, how the second letters change among themselves, and so on. The pattern may involve adding and subtracting fixed values alternately, sometimes wrapping beyond Z and returning to the beginning of the alphabet. Once we find the numeric changes, we convert back to letters.

Step-by-Step Solution:
Step 1: First letters: E, T, I, X. Positions: E = 5, T = 20, I = 9, X = 24. Step 2: Differences: 5 to 20 is +15, 20 to 9 is -11, 9 to 24 is +15. The pattern is +15, -11, +15, so the next step should be -11 again. Step 3: From 24 subtract 11: 24 - 11 = 13, which corresponds to M. So the first letter of the missing term is M. Step 4: Second letters: J, Y, N, C. Positions: J = 10, Y = 25, N = 14, C = 3. Step 5: Differences: 10 to 25 is +15, 25 to 14 is -11, 14 to 3 is -11. Continuing the +15, -11, +15, -11 pattern, the next difference must be +15. Step 6: From 3 add 15: 3 + 15 = 18, which is R. So the second letter is R. Step 7: Third letters: O, D, S, H. Positions: O = 15, D = 4, S = 19, H = 8. These differences are -11, +15, -11. Following the same alternating scheme, the next change must be +15. Step 8: From 8 add 15: 8 + 15 = 23, which is W. So the third letter is W, giving the term MRW.

Verification / Alternative check:
Write the full series with MRW: EJO, TYD, INS, XCH, MRW. For each column of letters, the pattern of +15 and -11 repeats in order, maintaining a consistent cyclic movement around the alphabet. No other option produces this neat alternation in all three letter positions, which verifies MRW as the correct completion of the sequence.

Why Other Options Are Wrong:
NRW, NSX, and MSX fail to respect the alternating +15 and -11 pattern. If any of these were used, at least one of the three letter positions would jump by a different amount, breaking the simple repeated scheme. Because exam patterns favour such regular alternations, these inconsistent options must be rejected.

Common Pitfalls:
One typical mistake is to check only the first letter and ignore the others, which can accidentally match an option by chance. Another is to overlook negative jumps or wrap around behaviour. Always handle all three letters systematically and pay attention to both additions and subtractions in cyclic series.

Final Answer:
The missing three letter term that continues the alternating pattern is MRW.