Answer: B.
![f(x) = 40e^x.](https://img.qammunity.org/2019/formulas/mathematics/middle-school/5ewocl780tssa1wls3emg7wsqpfab11els.png)
Explanation:
Given an exponential growth function graph.
We need to find the equation of given graph of exponential growth function.
From the graph, we can see that y-intercept is 40.
y-intercept represents initial value of y where x=0.
In the given options, we can see that second option
has initial value y=40 for x=0.
Therefore, for the given graph the exponential function would be
![f(x) = 40e^x.](https://img.qammunity.org/2019/formulas/mathematics/middle-school/5ewocl780tssa1wls3emg7wsqpfab11els.png)