Suppose a dye for staining cells stains the region where ribosomes are made. what would you expect to see inside the stained cells nucleus?

The RNA (ribonucleic acid) and the associated proteins forms the ribosomes. These ribosomes are the site of protein synthesis in a cell. Inside the stained cell nucleus, the nucleolus part of the cell can be seen. The nucleolus is the part where the all the ribosomes of the cell are assembled.

Hence, the answer is 'nucleolus'.