Answer: Option D
Ohm, volt, and ampere are units of electrical measurements. Ohm is the unit of electrical resistance, volt is the unit of electrical potential or electromotive force, and ampere is the unit of electric current.
Watt is the unit of electrical power, which is defined as the rate at which work is done or energy is transferred. It is named after James Watt, a Scottish engineer who made significant contributions to the development of the steam engine.
The formula for electrical power is given by:
Power (P) = Voltage (V) x Current (I)
where P is the power in watts (W), V is the voltage in volts (V), and I is the current in amperes (A).
Hence, the unit of power, watt, is equivalent to the product of the units of voltage and current, i.e., volt-ampere.
Light is not a unit of measurement. It refers to electromagnetic radiation that is visible to the human eye.
Metre is the unit of length in the International System of Units (SI).
Hour is the unit of time, which is equal to 60 minutes or 3,600 seconds.
In conclusion, option D, Watt, is the correct answer as it is the unit of electrical power, which is the product of voltage and current.