Final answer:
In the endosome, TLR-3, TLR-7, TLR-9, and TLR-8 (in humans) are the Toll-like receptors that detect viral and pathogenic nucleic acids.
Step-by-step explanation:
The Toll-like receptors (TLRs) that are expressed in the endosome include TLR-3, TLR-7, TLR-9, and often TLR-8 in humans. These TLRs are responsible for detecting nucleic acids from viruses and other pathogens within the cell's endosomes, which are compartments involved in sorting and processing materials internalized by the cell. Therefore, the correct answer to the question 'Which TLRs are expressed in the endosome?' is b) TLR-3, TLR-7, TLR-9, and in humans often TLR-8.