Answer: Option C.
Step-by-step explanation:
A function goes trough the x-axis when f(x) = 0 for some value of x.
For example, when we say that a quadratic function has no real zeros, this means that the determinant is less than zero, so the roots of the equation:
a*x^2 + b*x + c = 0
are complex roots, this means that for the function:
f(x) = y = a*x^2 + b*x + c
there is not a real number x such f(x) = 0
So the correct option is C.