The correct answer is By 44th Constitution Amendment Act. Explanation & Key Takeaways: National Emergency • A national emergency can be declared on the basis of war, external aggression, or armed rebellion. • The Constitution employs the expression ‘proclamation of emergency’ to denote an emergency of this type. Grounds of declaration: • Under Article 352, the president can declare a national emergency when the security of India or a part of it is threatened by war or external aggression, or armed rebellion. • The President can declare a national emergency even before the actual occurrence of war or armed rebellion or external aggression • When a national emergency is declared on the grounds of ‘war’ or ‘external aggression’, it is known as an ‘External Emergency’. • On the other hand, when it is declared on the grounds of ‘armed rebellion’, it is known as an ‘Internal Emergency’. • The term ‘armed rebellion is inserted from the 44th amendment. Hence option 1 is correct. • Before this term, it was known as an internal disturbance.