A linear function is a straight line, so that's clearly not it
A quadratic function has one point where is switches from going up to going down (or down to up), but this has two, so that's not it.
A cubic function has 2 points where it goes from down to up or up to down, so this may just work.
An exponential function has a constant to the power of something, so it's either staying constantly up or down after 0 or jumping up and down with every x value, which it isn't doing.
Logarithmic functions are similar to exponential functions in that it usually stays either going up or down the whole time.
Using our definitions, a cubic function is the only one that fits