A random poll of $1,200$ registered voters in a state indicated that $45\%$ plan to vote for Candidate A in the upcoming election. Based on these results, which of the following statements must be true?

I. The exact percentage of all registered voters in the state who plan to vote for Candidate A is $45\%$.
II. Any future poll of $1,200$ registered voters from the same state will find that exactly $45\%$ plan to vote for Candidate A.
III. A poll of $1,200$ registered voters in a neighboring state will find that exactly $45\%$ plan to vote for Candidate A.