According to the NCERT text, Vasectomy is a surgical method of sterilisation where a small part of the vas deferens is removed or tied up. This intervention works by blocking gamete transport and thereby preventing conception . It does not prevent spermatogenesis (sperm production); sperm are still produced but are prevented from entering the semen. The other options are correctly matched: IUDs increase phagocytosis and suppress motility , hormonal contraceptives inhibit ovulation and retard sperm entry , and barrier methods prevent the physical meeting of gametes .