1. Initial Configuration (12:00 hrs): The pattern \(R\) represents the initial configuration of the two dials \(P\) and \(Q\) at 12:00 hrs.
2. Rotation of Dial Q: Dial \(Q\) rotates 90 degrees clockwise every 15 minutes. Between 12:00 hrs and 13:30 hrs (1 hour and 30 minutes), \(Q\) completes:
\[
\frac{90}{15} \times 90 = 540 \text{ degrees}.
\]
Since \(540^\circ = 360^\circ + 180^\circ\), \(Q\) rotates by an effective 180 degrees clockwise.
3. Rotation of Dial P: Dial \(P\) rotates 45 degrees anticlockwise every 30 minutes.
Between 12:00 hrs and 13:30 hrs, \(P\) rotates:
\[
45^\circ \times \frac{90}{30} = 135 \text{ degrees anticlockwise}.
\]
4. Combined Rotation Effect: The combined rotations of \(P\) and \(Q\) determine the visibility pattern. After applying these rotations:
- \(Q\) shifts 180 degrees clockwise.
- \(P\) shifts 135 degrees anticlockwise.
The resulting pattern aligns with Option C.
Conclusion: The correct pattern at 13:30 hrs is \(C\).