Answer:
a(x)
Step-by-step explanation:
All the function, first of all, are increasing. We can see that from the fact that they are going upwards as we go towards the right.
Now, to see the increasing rate (faster or slower), we need to see the "slopiness" of the functions. Which ever has a slope greatest, that one is increasing the fastest.
The more the elevation, the more the slope. Now, looking at the functions, we see the greatest slope is that of the function a(x), pink one. It is the steepest.
Hence, a(x) is the answer.
