I got a multiple choice saying "Ini bukuAnda". I guess there should be a space between buku and Anda?

I was marked wrong for the correct response, down to the letter. Why?

'Buku ini kamu' is that not a correct response too. I have completely lost my confidence and i am totally confused i am thinking of trying another platform to see if i have the same issues. I have been studying for 60 day and i am a few points of level 14 but i feel like a complete moron using this soft ware???