So there are two things:
Domain and Range
Domain is the x value
and Range is the y value
THE Y VALUE IS ALWAYS DEPENDENT ON THE X VALUE
Therefore, the range is always dependent on the domain
In this line, there are arrows at the end of the line meaning that it goes on and on
If you look at it closer, the x value goes on and on without limitations
But the y value changes based on where the x value is, so it can't go anywhere it wants like the x value can
Therefore, if the x value or DOMAIN is infinite, that's the same as saying the *Domain is limited to all real numbers* since all other options restrict the x value AND because the term "all real numbers" basically means "infinite" in graphing