(D) Panchayat
The Constitution was amended in 1992 to reserve one-third of seats for women in Panchayati Raj bodies (panchayats and municipalities).
The textbook (Chapter 3) clearly states that the 73rd and 74th Constitutional Amendment Acts (1992) made it mandatory to reserve one-third of seats for women in local government bodies — panchayats and municipalities. This is the only institution among the options where reservation for women was introduced by a constitutional amendment in 1992. Note: Lok Sabha/State Assembly women's reservation (33%) came only via the Nari Shakti Vandan Adhiniyam, 2023 — much later.