"Who put this book on the desk?"

Translation: Siapa yang menaruh buku ini di atas meja?

[kuyaC]

I wrote the same thing without "yang". Isn't that correct?

[WayangOrang]

'yang' cannot be left out here.

It's explained in one of the grammar topics in the forum.

..edit... :
this topic :

Apa, Siapa, Tips & Notes, Addendum.
https://forum.duolingo.com/comment/31279456

[Sander271100]

Isnt meja tulis Indonesian for desk? Meja just means table