A mixed-case letter series is given with one term missing. Choose the correct term that will complete the sequence: AbCdE, DeFgH, GhIjK, JkLmN, ?

Introduction / Context:
This problem presents a series of five-letter strings where the letters follow a strict alphabetical order and the case alternates. The sequence is AbCdE, DeFgH, GhIjK, JkLmN, ?. You need to recognise both the letter pattern and the case pattern to determine the correct next term.

Given Data / Assumptions:

• Given series: AbCdE, DeFgH, GhIjK, JkLmN, ?
• Each term contains five letters.
• Letters are in alphabetical order with alternating uppercase and lowercase.
• The sequence starts with A and progresses forward through the alphabet.

Concept / Approach:
We first examine the sequence of letters without worrying about case. Then we look at how the starting letter of each term shifts. Finally, we confirm the pattern of uppercase and lowercase positions inside each term. Once these patterns are clear, it is easy to build the missing term and match it to the correct option.

Step-by-Step Solution:
Step 1: Observe the letters of each term. AbCdE uses letters A, b, C, d, E → underlying letters A, B, C, D, E. DeFgH uses letters D, e, F, g, H → underlying letters D, E, F, G, H. GhIjK uses letters G, h, I, j, K → underlying letters G, H, I, J, K. JkLmN uses letters J, k, L, m, N → underlying letters J, K, L, M, N. Step 2: Note that each term represents a sequence of five consecutive letters in the alphabet. Step 3: Determine the starting letter of each term: A, D, G, J. Positions: A = 1, D = 4, G = 7, J = 10. Each starting letter moves forward by +3 (1 → 4 → 7 → 10). Step 4: The next starting letter is J (10) + 3 = 13, which is M. Step 5: The next term should therefore be the sequence M, N, O, P, Q (five consecutive letters). Step 6: Look at the case pattern. In each term, the letters appear as uppercase, lowercase, uppercase, lowercase, uppercase. Step 7: Apply the same pattern to M, N, O, P, Q, giving MnOpQ (M uppercase, n lowercase, O uppercase, p lowercase, Q uppercase).

Verification / Alternative check:
The extended series becomes: AbCdE, DeFgH, GhIjK, JkLmN, MnOpQ. Each term is a block of five consecutive letters, and the case alternates uppercase, lowercase, uppercase, lowercase, uppercase. The starting letters follow a +3 pattern: A, D, G, J, M. The term MnOpQ is therefore perfectly consistent with the established pattern.

Why Other Options Are Wrong:
Option A (OpQrS): This starts at O rather than M and does not maintain the correct +3 jump from J. Option B (NoPqR): The underlying letters N, O, P, Q, R do not correspond to the required M, N, O, P, Q block, and the starting letter is incorrect. Option D (LmNoP): Here the underlying sequence is L, M, N, O, P, so the starting letter L is not the correct +3 step from J. The case pattern also does not match as cleanly as MnOpQ.

Common Pitfalls:
Some students focus only on the letters and ignore case, or vice versa. Another mistake is to assume a simple +1 progression in starting letters rather than carefully measuring the step. Always check both the underlying letter sequence and the pattern of capitalisation when dealing with mixed-case series questions.

Final Answer:
The missing term in the series is MnOpQ, which corresponds to option C.