Answer: Choice A) There must be a vertical asymptote at x = c
Explanation:
The first limit says that as x approaches c from the left side, the f(x) or y values approach negative infinity. So the graph goes down forever as x approaches this c value from the left side.
The limit means that as x approaches c from the right side, the y values head off to positive infinity.
Either of these facts are enough to conclude that we have a vertical asymptote at x = c. We can think of it like an electric fence in which we can get closer to, but not actually touch it.