Easy# Definition of Vertical Asymptote

APCALC-ENCJLG

Given $\mathop {\lim }\limits_{x \to {3^ - }} f(x) = \infty$. Which of the following must be true?

I.$f(x)$ has a horizontal asymptote at $y=3$II.$f(x)$ has a vertical asymptote at $x=3$III.$f(x)$ is unbounded