Which of the following is used for determining the value of 1 ampere?

Electric current ($\text{I}$) is defined as the rate of flow of electric charge ($\text{Q}$) through a conductor per unit time ($\text{t}$). The formula is given by:
$$\text{I}=\frac{\text{Q}}{\text{t}}$$

The SI unit of electric current is the Ampere ($\text{A}$), the unit of charge is the Coulomb ($\text{C}$), and the unit of time is the second ($\text{s}$). Therefore, 1 Ampere corresponds to the flow of 1 Coulomb of charge per second:

$$\text{A}=\frac{1\text{C}}{\text{s}}$$