Which of the following is the supreme in a federal system?

In a federal system, the supreme authority is usually the Constitution. The Constitution defines the structure of the government, allocates powers between the central government and the state or regional governments, and provides a framework for protecting individual rights and freedoms. It is the highest law of the land and all other laws and actions of the government must be in line with its provisions. The Constitution also establishes the powers and limits of the legislative, executive, and judicial branches of government, and sets the rules for their interactions. Therefore, the Constitution plays a pivotal role in a federal system and is considered the supreme law.