Because they just went through a revolution, and the fear of having limited rights and no say was still current at the time. States wanted to know that people would be protected, and their rights would be preserved and defended. =)
"<span>(c)the ability of citizens to vote" is the best answer but this is very misleading. A referendum is when the citizens vote directly on a specific issue of policy. It's not their ability to vote for mayors, legislators, etc.</span>
They are choices (A, C, E, F, and G).
By the way, these pillars are listed in a few hadiths - that's their origin.
They wanted to stop communism. It was spreading and this was the start of us trying to prevent it.