The correct answer is option 1 - Keshvananda Bharati Case. In the Keshvananda Bharati Case, the Supreme Court of India proclaimed the Basic Structure Doctrine, which refers to the idea that certain fundamental principles of the Constitution cannot be altered or destroyed by any amendment by the Parliament. The court held that while Parliament has the power to amend the Constitution, it cannot change its basic structure, which includes principles like federalism, secularism, democracy, separation of powers, and judicial review. The court`s decision in this case has had a significant impact on the interpretation and evolution of the Indian Constitution. It is important to note that while the other options mentioned are significant cases in Indian constitutional law, they do not specifically relate to the proclamation of the Basic Structure Doctrine.