The is should be C, Im not 100% sure though...
Well assuming the original cell is a prokaryotic, you wouldn't be able to remove the nucleus because prokaryotic cells don't have a nucleus to begin with. if this doesn't help then: The cell would lack genetic information.
The answer is A, Viruses
Viruses cannot reproduce on their own , so they have to inject their DNA or RNA into the nucleuus of a cell. By doing this, the virus will take over that cells and within times, that cells will pop up and producing more viruses.
This reproduced virus will repeat the same process until our immune systems stop them
