Step 1: Understanding the circuit.
The circuit contains two diodes arranged such that they rectify the alternating current (AC) input waveform. In this type of circuit, the diodes will conduct current during the positive half-cycle and block current during the negative half-cycle, resulting in a half-wave rectified output across PQ. The output waveform will only allow the positive portion of the AC signal to pass.
Step 2: Conclusion.
The correct answer is option (C) because the voltage waveform across PQ will be half-wave rectified, with the negative portion of the AC waveform being blocked by the diodes.