I know about another meaning "warehouse", but living in Poland and often see "magazyn" on covers of magazines :) I like that word more than czasopismo and Pani from kiosks understand me, that's good :))
My Polish polish-teacher said magazyn and so do the study book. .... and my Polish sister-in-law. I was confused, though, that the only option with magazyn used lubisz and not lubię... This was a tricky exercise
We accept "magazyn" indeed, but we don't teach it. Those "choose 1 of the 3 answers" exercises sometimes use a word from the accepted answers (a word that the learners aren't expected to know) but there's always a mistake somewhere else in the sentence.