The correct option is B Curbing subversive and unconstitutional activities
The 42nd amendment Act 1976 added a new part in the constitution part IVA. It incorporated the fundamental duties by inserting a new article 51A below article 51. The objective of incorporating the fundamental duties is to place before the country a code of conduct, which the citizens are expected to follow. The citizens enjoying the fundamental rights must respect the ideals of the constitution, to promote harmony and spirit of the brotherhood.