Answer:
Option: A is the correct answer.
Explanation:
Clearly from the graph we could observe that the graph is a decay exponential function as the graph of the function is decreasing with the increasing value of x.
Hence, the rate has to be less than 1.
So, option: B and D are ruled out as they represent a growth exponential function.
Also from the graph given in the question we could observe that when x=0 the value of y is:
y=4
So, the exponential function that is represented by the graph is: