Detailed Solution:
The correct answer is “Protection of environment”.
The protection and improvement of the environment are mentioned both in the Directive Principles of State Policy (Article 48A) and in the Fundamental Duties (Article 51A) of the Indian Constitution.
Article 48 of the Constitution of India is one of the Directive Principles which directs the state to make efforts for banning animal slaughtering of cows and calves and other milch and draught cattle.