Alphabet series – supply the missing letter Sequence: A, D, H, M, ?, Z

Introduction / Context:
Many alphabet sequences are based on increasing step sizes. Here, consecutive jumps grow by 1 each time, and you must continue that progression to find the missing letter before Z.

Given Data / Assumptions:

• Sequence: A, D, H, M, ?, Z.
• Alphabet positions A=1, …, Z=26.

Concept / Approach:
Translate letters to indices and compute the deltas between successive terms. If the deltas follow +3, +4, +5, … then you should continue with +6, +7, etc., until reaching Z.

Step-by-Step Solution:

Verification / Alternative check:
Differences form a clean arithmetic sequence: 3, 4, 5, 6, 7. With S inserted, the pattern brings you perfectly to Z.

Why Other Options Are Wrong:

• T (20) would be +7 from M, skipping the required +6 step and preventing a final +7 to Z.
• G or N do not follow the increasing-difference ladder from M.
• U (21) similarly mismatches the necessary +6 step.

Common Pitfalls:
Jumping directly to Z from M without honoring the incremental step-size growth; miscounting letter positions.

Final Answer:
S