Which of the following best describes the graph below?
a. it is a many-to-one function.
b. it is a function, but it is not one-to-one.
c. it is a one-to-one function.
d. it is not a function.

D. It is not a function.

Step-by-step explanation:

Radius of given circle = 4 units

Center = (0,0)

Equation of circle :

where (h,k) is the center

So, equation of given circle =

Substitute x = -1

So, since at one value of x we are getting the two values of y .

A function is a relation that for each input, there is only one output.

So, It is not a function.

Hence Option D is true.