Answer:
I would say that the best answer is A.
Step-by-step explanation:
Both Bacteria and Archaea, lack a nucleus and are unicellular. Most Archaea have a Cell wall, however there are a few exceptions, all Bacteria have a cell wall. Maybe the biggest difference between the two however, is where they thrive. Archaea live in extreme conditions, while bacteria don't. Due to this, I would say that the best answer is A, because this is the only question with a major difference in answers.