The correct answer is C. ampere.
An ampere (A) is the SI unit of electric current. It is the flow of one coulomb of electric charge per second. The ampere is one of the seven base units in the International System of Units (SI). It is named after André-Marie Ampère, a French physicist and mathematician who is considered one of the founders of electromagnetism.
The ohm (Ω) is the SI unit of electrical resistance. It is the resistance of a conductor when a constant current of one ampere produces a voltage drop of one volt across the conductor. The ohm is named after Georg Ohm, a German physicist who is considered one of the founders of electrical science.
The watt (W) is the SI unit of power. It is the rate at which energy is transferred or converted. The watt is named after James Watt, a Scottish inventor and engineer who is considered one of the founders of the Industrial Revolution.
Therefore, the unit of current is the ampere.