Concept:A co-operative society follows the democratic rule of “one man one vote”.Explanation:In a co-operative society, every member has only one vote.This right does not depend on the number of shares or the capital contributed by the member.For example, a member holding 100 shares still gets only one vote.This ensures equal control and democratic management for all members.Sole proprietorship, partnership, and public company do not follow this principle.Answer:C. co-operative society