Concept:A monarchy is a system of government in which one person rules, usually for life, and power is often passed down within a family.
Explanation:The most common and defining feature of a monarchical government is that succession to the throne is by heredity, meaning the ruler's child or relative inherits the position.
In a monarchy, the ruler generally does not have a fixed tenure, as the position is held for life.
Separation of powers is not absolute in a monarchy because the monarch often controls several arms of government.
Members of the executive are not elected by the people in a monarchy; they are appointed or inherit their positions.
Therefore, the basic feature among the options is succession through heredity.
Answer:A. succession is through heredity.