Which Constitutional Amendment Act introduced the GST (Goods and Services Tax) in India?

Which of the following Constitution Amendment Acts introduced GST (Goods and Services Tax) in course of inter-state trade or commerce?

Which of the following Constitution Amendment Acts introduced GST (Goods and Services Tax) in course of inter-state trade or commerce ?

By which Constitutional Amendment Act was Sikkim granted full statehood in India?

Which Constitutional Amendment Act provided constitutional status to Urban Local Bodies in India?

By which Constitutional Amendment Act were the words 'Socialist', 'Secular' and 'Integrity' added to the Preamble of the Indian Constitution?