Answer:
Option C. exponential decay function
Step-by-step explanation:
In this problem we have a exponential function of the form
![y=a(b^x)](https://tex.z-dn.net/?f=y%3Da%28b%5Ex%29)
where
y ---> is the money that is in the bank
x ----> number of days
a ---> is the initial value or y-intercept
b is the base of the exponential function
r ---> is the rate of change
b=(1+r)
In this problem we have that
Each day 1/2 of the money that is in bank value is removed
so
---> is negative because is a decreasing function
The value of b is equal to
![b=1-r=1-0.50=0.50](https://tex.z-dn.net/?f=b%3D1-r%3D1-0.50%3D0.50)
![y=a(0.50^x)](https://tex.z-dn.net/?f=y%3Da%280.50%5Ex%29)
The value of b is less than 1
b<1
That means -----> Is a exponential decay function