The correct option is Ampere.
Explanation
The International System of Units (SI) is the globally accepted standard for measurement. It consists of seven base units from which all other units are derived. Electric current is a fundamental physical quantity defined as the rate of flow of electric charge.
Option Analysis
- Ampere is correct: The Ampere (symbol: A) is the SI base unit of electric current. It is named after the French physicist André-Marie Ampère. One ampere represents a flow of one coulomb of charge per second.
- Volt is incorrect: The Volt (symbol: V) is the SI derived unit of electric potential difference (voltage) and electromotive force.
- Ohm is incorrect: The Ohm (symbol: Ω) is the SI derived unit of electrical resistance.
- Joule is incorrect: The Joule (symbol: J) is the SI derived unit of energy, work, or quantity of heat.
Key Takeaway: The Ampere is one of the seven fundamental base units in the SI system, specifically measuring the magnitude of electric current.