Hindi in Devanagari script was adopted as the official language of the Union by the Constituent Assembly on which date?

Hindi in Devanagari script was adopted as the official language of the Union by the Constituent Assembly on which date?
हिंदी को देवनागरी लिपि में संघ की राजभाषा के रूप में संविधान सभा ने किस तिथि को अपनाया था?

26 January 1950 / 26 जनवरी 1950 14 September 1949 / 14 सितंबर 1949 14 September 1953 / 14 सितंबर 1953 15 August 1947 / 15 अगस्त 1947