The correct answer is A) Voltage. In a parallel circuit, the voltage across each component is the same. This is because all the components are connected to the same voltage source, so the voltage is constant across the entire circuit. The other options are incorrect because in a parallel circuit, the resistance and impedance can vary for each component, and the current will divide up differently through each component based on their individual resistance/impedance. Only the voltage remains the same across all components in a parallel circuit.