Which Amendment of the Indian Constitution inserted the two words – ‘Socialist’ and ‘Secular’ in the Preamble?

Which Amendment of the Indian Constitution inserted the two words – ‘Socialist’ and ‘Secular’ in the Preamble? [SSC CGL Exam 02/09/2016, Shift I], [SSC CGL Exam 06/09/2016, Shift III], [SSC CPO SI, ASI Exam 06/06/2016, Shift II], [SSC CPO Sub - Inspector Exam 06/09/2009], and [SSC Combined Matric Level Exam 05/05/2002, Shift II]

          a) 28^th

          b) 40^th

          c) 42^nd

          d) 52^nd