It's actually called ferromagnetic but they didn't put that as a option so i'm not sure which one they are referring to but i'ma go with i think the answer is D:A permanent magnet since once they combine they are permanent and they down break lose or go away
Yea that's my answer sorry if it is incorrect Have a great day and spread love into the world!Btw that's my memo just so u know--know XD...!!!!!.