Answer:
The correct answer would be A. It has DNA that is not contained within a nucleus.
The main difference between prokaryotic and eukaryotic cell is the absence of a well-defined nucleus and other membrane-bound organelles like the Golgi body, mitochondria et cetera in a prokaryotic cell.
The DNA in the prokaryotic cell floats freely in the cytoplasm in the region called nucleoid which means nucleus-like.
Thus, an observation like the absence of a nucleus can provide the evidence that a cell is most likely a prokaryote.
