The correct options are
A The provisions of the Constitution can be amended, but the 'Basic Structure' of the Constitution should not be compromised.
C The doctrine of 'Basic Structure' is intended to preserve the essence of the Constitution.
According to the doctrine of 'Basic Structure', some principles of the constitution are so significant that they can't be changed or amended. These principles or the 'Basic Structure' are the essence of the constitution. For example, principles like federal character, constitutional supremacy, sovereignty of the nation, and provisions for justice and the welfare state are part of the 'Basic Structure' of the constitution.