To prevent a DC return between source and load, it is necessary to use

Answer: Option C

Option A: Resistor between source and load
A resistor between the source and load allows both AC and DC components of the signal to pass. It does not block the DC component, which is not suitable when the goal is to prevent DC return. Therefore, this option is incorrect.

Option B: Inductor between source and load
An inductor primarily opposes changes in current and allows DC to pass through while blocking high-frequency AC signals. Since it does not block DC, it cannot prevent a DC return. Hence, this option is incorrect.

Option C: Capacitor between source and load
A capacitor blocks DC components and allows AC signals to pass through due to its property of impedance, which is inversely proportional to frequency. This makes it the ideal component to prevent DC return between the source and load. Therefore, this option is correct.

Option D: Either A or B
Neither a resistor nor an inductor can effectively prevent DC return as they allow DC to pass through. Thus, this option is incorrect.

Conclusion:
To prevent a DC return between the source and load, it is necessary to use a capacitor (Option C).