The correct option is D Greece
Republic form of government refers to democratic elected ruler or head of state instead of a monarch or ruling dynasty. Though Democratic process of government formation at widespread level is a recent phenomena, we can observe this practise in some ancient states. Greek Civilisation had this system of election of heads/government for it's Poleis (City States) during Iron Age itself (beginning from 9th century B.C.). These principles of governance spread from Greece are considered a cornerstone for western civilisation.