The correct option is C IUD
The intra uterine devices (IUDs) called hormone releasing IUDs inhibit ovulation, make cervix unreceptive to sperms and make the uterus unsuitable for implantation. Examples of hormone releasing IUDs are progestasert & LNG-20.
Diaphragm and condoms are used in barrier method. Barrier method and natural method prevent ovum and sperms from physically meeting.