hi,how r u ?
first of all we say in arabic ما هو الفن ؟
because the pronoun [ هي =pronounced in arabic"hia" ] which means [ she ] is useing for feminine , while the pronoun [هو pronounced "hoa" ] which means [ he ] for masculine .
and the word [ الفن ="al-fnn" ] which means [ art ] is masculine in arabic.
so
ما هو الفنّ؟ means [ what is art ?]
prononced in arabic " ma hoa al-fann ? "
i hope that I answer what you are really mean by your question.
best wishes =)