Which statement best describes the function below?
f(x)=2x^3+2x^2-x

a. it is not a function
b. it is a many-to-one function
c. it fails the vertical line test
d. it is a one-to-one function

Based on the graph I attached, the best answer is OPTION B. 

It is a function because it passes the vertical line test (which means the answer cant be A or C) and it fails the horizontal line test which means it is NOT one-to-one but instead many-to-one