Explanation:

- Option 1: VII Schedule to the Constitution

- The VII Schedule of the Indian Constitution deals with the division of powers between the Union and the States. It does not directly address the separation of the judiciary from the executive.

- Option 2: Judicial decision

- Judicial decisions have played a role in emphasizing the importance of separating the judiciary from the executive, but they are not the origin of this principle.

- Option 3: Directive Principles

- The Directive Principles of State Policy, specifically Article 50, enjoin the separation of the judiciary from the executive to ensure the independence of the judiciary.

- Option 4: Preamble

- The Preamble sets the guiding principles and values of the Constitution but does not specifically mention the separation of the judiciary from the executive.