Option 1 -> Central Goods and Service Tax Act was enacted under Article 246A to levy GST on intra-state supplies by the Centre.
Option 2 -> Integrated Goods and Service Tax Act was enacted under Article 246A to levy GST on inter-state supplies and imports.
Option 3 -> States Goods and Service Tax Act was enacted under Article 246A to levy GST on intra-state supplies by States.
Option 4 -> Regional Goods and Service Tax does not exist and was never enacted under Article 246A.
Hence, Regional Goods and Service Tax -> Article 246A, inserted by the 101st Constitutional Amendment Act 2016, provides concurrent power to Parliament and State Legislatures to make laws on GST. Under this provision, three acts were enacted: CGST Act (for Central Government), SGST Act (for State Governments), and IGST Act (for inter-state transactions). There is no such act as "Regional Goods and Service Tax" in the Indian GST framework -> correct