Which one of the given groups of structures are haploid?

The correct answer is Option (4) → Spermatids, spermatozoa, secondary spermatocytes

Option (1) Spermatogonia, spermatids, spermatozoids — Incorrect. Spermatids and sperms are haploid, but spermatogonia are diploid. They divide only by mitosis and have 46 chromosomes.

Option (2) Sertoli cells, sperms, secondary spermatocytes — Incorrect. Sertoli cells are not germ cells. They line the seminiferous tubules and nourish the developing sperms. Like other body cells, they are diploid.

Option (3) Spermatogonia, primary spermatocyte, sertoli cells — Incorrect. All three are diploid. The primary spermatocyte is the cell that is about to undergo meiosis, so it still has 46 chromosomes.

Option (4) Spermatids, spermatozoa, secondary spermatocytes — Correct. The chromosome number is halved in the first meiotic division, which forms the secondary spermatocytes. Every cell formed after that step is haploid.

NCERT Extract:
Gametogenesis – “… In testis, the immature male germ cells (spermatogonia) produce sperms by spermatogenesis that begins at puberty. The spermatogonia (sing. spermatogonium) present on the inside wall of seminiferous tubules multiply by mitotic division and increase in numbers. Each spermatogonium is diploid and contains 46 chromosomes. Some of the spermatogonia called primary spermatocytes periodically undergo meiosis. A primary spermatocyte completes the first meiotic division (reduction division) leading to formation of two equal, haploid cells called secondary spermatocytes, which have only 23 chromosomes each. The secondary spermatocytes undergo the second meiotic division to produce four equal, haploid spermatids (Figure 2.5). … The spermatids are transformed into spermatozoa (sperms) by the process called spermiogenesis.”