Option 1: 2016 -> GST was not yet operational; it was still in the planning and legislative phase.
Option 2: 2018 -> GST had already been implemented by this year.
Option 3: 2017 -> GST was launched on July 1, 2017.
Option 4: 2014 -> GST was not operational; it was still under discussion.
Hence, Option 3: 2017 -> The Goods and Services Tax (GST) became operational in India on July 1, 2017, replacing multiple indirect taxes levied by the central and state governments. It was launched at a midnight event in the Central Hall of Parliament, marking a significant tax reform in India's economic history. -> correct