The correct option is Coulomb.
Explanation
The International System of Units (SI) establishes standard units for measuring physical quantities. Electric charge is a physical property of matter that causes it to experience a force when placed in an electromagnetic field. Its unit is derived from the fundamental unit of electric current.
Option Analysis:
- Coulomb is Correct: The Coulomb (C) is the SI unit of electric charge. It is defined as the quantity of electricity transported by a constant current of one ampere flowing for one second ($1 \text{ C} = 1 \text{ A} \times 1 \text{ s}$).
- Ampere is Incorrect: The Ampere (A) is the SI base unit of electric current.
- Watt is Incorrect: The Watt (W) is the SI unit of power, defined as one joule per second.
- Tesla is Incorrect: The Tesla (T) is the SI unit of magnetic flux density.
Key Takeaway:
Electric charge ($Q$) is the product of electric current ($I$) and time ($t$). Therefore, the SI unit Coulomb is dimensionally equivalent to Ampere-second ($A \cdot s$).