To determine if a function is even or odd, we start from its definition.
While for an EVEN FUNCTION we have: F(x) = F(-X), for an ODD FUNCTION we have F(-X) = -F(X)
Now, from this, we can check that all the values the function achiever for any X value, the -X has same height. The function presents a symmetry over the Y-axis, and this implies in a function to be an EVEN FUNCTION.
And from the solution developed above, the only statement that is true is the
C) The function is an even function.