Solve this Alphabetical Series question: Find the next letter in the series: C, O, E, R, G, U, ?

I, option D.

Rebuild and verify the complete alphabet-position pattern.

J, H, K break a clue, direction, transition or operation.

Replay the rule from the first clue or term and test every intermediate step.

An Alphabetical Series is an ordered sequence of letters or letter groups connected by a consistent rule, such as a fixed gap, increasing jump, alternating movement or two interwoven sequences. The solver identifies the rule and finds the missing or next term.

Write A=1 to Z=26 positions, calculate the gap between consecutive letters, and check odd and even positions separately. Test fixed gaps first, then increasing gaps, backward movement, opposite letters and paired patterns. Verify the rule across every known term.