Option 1 -> 2013 was when the GST Bill was initially introduced in Parliament, but it did not come into effect this year.
Option 2 -> 2015 saw continued discussions and debates on GST in Parliament, but implementation had not yet occurred.
Option 3 -> 2017 is when the GST Act was officially implemented on July 1st, creating a unified indirect tax system across India.
Option 4 -> 2019 is after GST implementation; by this time, the tax system was already operational for two years.
Hence, Option 3 (2017) -> The Goods and Services Tax Act came into effect on July 1, 2017, replacing multiple indirect taxes and creating a unified tax structure across India, fulfilling the vision of "One Nation, One Tax and One Market" -> correct