Answer:
Step-by-step explanation:
The first function is given as, .
Now, the value of this function increases i.e. value of f(x) increases as the x-value increases because .
Now, the second function is given as, .
This function can not be considered as a continuous function because .
Again, the third function is given as, .
This function can also not be considered as a continuous function because .
Finally, the fourth function is given to be, .
In this function, the value of f(x) continuously decreases as the value of x increases, because .
Therefore, this function represents exponential decay. (Answer)