Final answer:
The best explanation of "one person, one vote" is that everyone's vote should count equally, embodying the core principle of equality in democratic elections.
Step-by-step explanation:
The statement that best explains the meaning of "one person, one vote" is d. All people's votes should count equally. This principle is fundamental in democratic societies where each individual's vote is supposed to have the same weight in an election, ensuring fair representation. It aims to prevent disproportionate influence and upholds the idea that all citizens, regardless of status or location, should have an equal say in the democratic process.