Different roles of Parliament executive and judiciary in a policy decision show which principle?

Correct answer: Separation and balance of powers

In a democracy, power is not placed entirely in one institution. Parliament discusses and makes laws, the executive carries out laws and policies, and the judiciary interprets the Constitution and reviews whether government action is lawful. Their responsibilities are different, but they are connected. Each institution has limits and may check the actions of another. This arrangement reduces the danger of arbitrary rule and protects constitutional government.

Option A is correct because the separate roles of Parliament, the executive, and the judiciary show separation of powers together with checks and balance. Parliament cannot simply perform every executive or judicial task, and the executive is not free to ignore laws or constitutional limits. The judiciary also does not govern the country like an elected cabinet. The other options do not describe this institutional relationship: hereditary rule depends on family succession, one-party rule concerns political competition, and private trade is unrelated.