Answer:
b. Primary spermatocytes
Explanation:
Primary spermatocytes are the diploid cells present in seminiferous tubules of testes. These diploid cells enter meiosis I and produce haploid cells. Each diploid primary spermatocyte produces two haploid cells by meiosis I which are called secondary spermatocytes.
The secondary spermatocytes then enter meiosis II to produce sperms.