Step 1: Analyse options.
- The sequence $[L], [m], [|], [J]$ represents a rotational or reflective transformation of line segments.
- Observing the shift from $L$ to $J$, the pattern involves a $180^\circ$ rotation or a specific flip of the "hook" element.
Step 2: Conclusion.
Figure A provides the logical continuation of this segment transformation.
Final Answer: (a) A