Step 1: Carefully observe the arrangement of the broken plate in Figure A. It consists of six pieces, but only five are placed. The missing piece must complete the overall structure.
Step 2: Analyze the shape and design of the missing portion. The curvature and pattern on the plate must align perfectly with the given options (\( P, Q, R, S \)).
Step 3: Compare each of the given choices with the missing space. Piece \( R \) matches the missing section precisely, both in terms of design continuity and shape.
Thus, the correct answer is option C (\( R \)).