The 42nd Amendment Act of 1976 significantly altered the Preamble of the Indian Constitution.
This amendment introduced three new words into the Preamble:
Based on the options provided and the historical context of the 42nd Amendment, these three words correspond to expressions (b), (c), and (d). Expression (a), not being among these three, was not added by this amendment.
Therefore, the correct combination includes (b), (c), and (d).