16.
The answer is: B
Explanation
The correct option is B: Article 51A (g).
This article states that it is the duty of every citizen of India to protect and improve the natural environment including forests, lakes, rivers and wildlife and to have compassion for living creatures. This article was added by the 42nd Amendment Act of 1976, which also introduced the concept of fundamental duties in the Indian Constitution. The article reflects the concern of the framers of the Constitution for the preservation and conservation of the environment, which is essential for the well-being of the present and future generations.