particular is different from special
'Seine' is used because the German word for clothing (Kleidung) is a feminine word thus you have to add the feminine suffix 'e' to the word Sein to form Seine. (Because 'his' precedes the feminine 'clothing')
I wrote "seine Klamotten sind einzigartig". I think it should be right too.
The English translation is simply wrong,it makes no sense whatsoever. Wahrscheinlich, we were told means probable, likely, so that's wrong too. All in all its a shocking piece of education.
I wrote "Seine Kleidung ist bestimmt". Is that also not possible. Mr dictionary says it is?