What is the function of copper ions in copper-releasing $IUDs$?

The method of natural contraception which requires correct knowledge of the menstrual cycle is

How do Intrauterine Devices $(IUDs)$ function as a method of birth control?

What is the purpose of contraceptive pills?
$I$. They inhibit ovulation and implantation
$II$. They alter the quality of cervical mucous to prevent or retard the entry of sperms
$III$. They prevent the ejaculated semen from entering the female vagina
$IV$. They inhibit spermatogenesis

Which one of the following is a hormone-releasing $IUD$?

Explain the difference between condoms and diaphragms.