Monosaccharide found in nucleolus is:

Explanation

The correct answer is pentose because ribose, a pentose sugar, is a component of RNA, which is synthesized in the nucleolus. The nucleolus is primarily involved in the production of ribosomes, which requires ribosomal RNA (rRNA). Hence, pentose sugars are integral to the structure of nucleic acids associated with the nucleolus. Erythrose and tetrose refer to sugars with four carbon atoms, which are not involved in nucleic acids. Hexose sugars have six carbon atoms and are primarily involved in energy processes rather than forming nucleic acids found in the nucleolus.