Element: Boron
Symbol: B
So answer is B
I think that work is being done on the books because they are being moved to their proper location and they will be sorted properly rather than lying on a table. Without lifting or carrying, you could sort the books by their genre or title name on the bookshelf so it will be sorted much more efficiently.
I’m not sure if this is the answer you are looking for but I hope it helps :)
