The correct answer is: C. Voltages are additive.
In a series circuit, the current is the same through all the elements. In a parallel circuit, the voltage is the same across all the elements. Therefore, the voltages are additive in both series and parallel circuits.
A. Elements have individual currents
This is true for a parallel circuit, but not for a series circuit. In a parallel circuit, each element has its own current. In a series circuit, there is only one current that flows through all the elements.
B. Currents are additive
This is true for a series circuit, but not for a parallel circuit. In a series circuit, the currents add up to the total current in the circuit. In a parallel circuit, the currents are not additive. The current through each branch of a parallel circuit is independent of the currents through the other branches.
D. Power are additive
This is not true for either a series or parallel circuit. The power in a circuit is the product of the voltage and the current. In a series circuit, the voltage and current are the same for all the elements, so the power is also the same for all the elements. In a parallel circuit, the voltage and current are different for each element, so the power is also different for each element.