The correct answer is option 1: Communist state. Democratic centralism is a principle that is specifically associated with communist states. It is a system in which decisions are made through a democratic process, but once a decision is reached, it is binding on all members of the party. This means that once a decision is made by the ruling communist party, it must be followed by all members of the party, even if they disagree with it. It is a way to ensure unity and cohesion within the party and to maintain control over the actions and decisions of its members. The other options are not correct because democratic centralism is not a characteristic of democratic, totalitarian, or socialist states.