Option (c) is correct as Intrauterine Devices (IUDs) increase phagocytosis of sperms within the uterus and the Cu ions released suppress sperm motility and fertilising capacity of sperms. Other statements can be corrected as IUDs can be removed as these are a reversible contraception method. IUDs are inserted by doctors or expert nurses in the uterus through vagina. IUDs do not affect gametogenesis.