Answer:
f(x)=5x^2-4x+5
Explanation:
A quadratic function always has a squared symbol (represented by ^2). The first answer is a linear function, the second answer is a linear function (squaring 0 results in 0, therefore it is canceled out), the third answer has ^2 (this is correct), and the fourth answer has a ^3 (this is a cube function; not quadratic)