The first "correct" answer said "clean up your ROOM" and the second one uses "bedroom." I wrote "clean your room" and lost a heart. Not Fair!
as it is in imperative, "your" fits much better... but it could be a part of "sua mãe quer que ele limpe seu quarto" (his mother wants him to clean his room).
I am having trouble understanding the use of certain articles. For example, why use "limpe o seu quarto" instead of "limpe seu quarto"? Is the "o" necessary? Is it indistinct? Is there a certain rule regarding this?