A
the Preamble of the Constitution
B
a Directive Principle of State Policy
C
the Seventh Schedule
D
the conventional practice
Correct answer: (b) a Directive Principle of State Policy
Explanation
- A
the Preamble of the Constitution
Preamble. Justice, liberty, equality, fraternity — not this separation.
- B
a Directive Principle of State Policy
A Directive Principle. Article 50: separate the judiciary from the executive in public services.
- C
the Seventh Schedule
Seventh Schedule. Lists of subjects, not this injunction.
- D
the conventional practice
Convention. The text is a DPSP, not mere practice.
Summary. Official key is (b). Article 50, a Directive Principle, enjoins the State to separate the judiciary from the executive in the public services of the State.