The correct answer is both current and voltage (option D). Ohm’s law describes the fundamental relationship between voltage and current in an electrical circuit. It states that the current (I) flowing through a conductor is directly proportional to the voltage (V) applied across it, given a constant temperature (R is the constant of proportionality, known as resistance). This law applies to a wide range of conductive materials and helps in understanding how voltage influences current flow through resistive elements. Ohm’s law is fundamental for analyzing and designing electrical circuits, determining the behavior of resistors, and calculating the power dissipation in circuits. It provides a foundational principle for engineers and technicians to predict and control current levels in various applications, from household electronics to complex industrial systems. Understanding Ohm’s law is crucial for ensuring the efficient and safe operation of electrical devices and systems.