Answer:
Nucleus.
Step-by-step explanation:
Eukaryotes and prokaryotes shows the different characteristics with each other. All bacteria are classified in the prokaryotes and plants, animal, fungi are classified in eukaryotes.
The main basis of prokaryotes and eukaryotes classification is the presence of nucleus. Nucleus is present in prokaryotes and absent in eukaryotes. Transcription and translation are coupled in prokaryotes but take in the different compartments into eukaryotes due to the presence of nucleus.
Thus, the correct answer is option (B).