The function $C\left(t\right)=\frac{80t}{t+4}$ (in $\text{ppm}$) represents the concentration of a solution, where $t\ge 0$ is the time in minutes. Determine the average rate at which the concentration changes over the interval $[0,5]$.

• A. $\frac{80}{9}\text{ ppm/min}$
• B. $\frac{400}{9}\text{ ppm/min}$
• C. $\frac{80}{3}\text{ ppm/min}$
• D. $\frac{400}{3}\text{ ppm/min}$