The correct answer is C.
The zygote is a single fertilized egg cell that the embryo develops from.
This one cell possesses one copy of DNA that is going to be passed to all other cells in the embryo because all other cells of the embryo develop through mitotic divisions of the zygote.
Therefore, if a mutation happens in the zygote DNA, all of the cells in the embryo are going to have it as well.
Answer: The correct answer is- Archaea and Eukarya.
As per the information about the (phylogenetic tree) given in the question,
the last branch of the phylogenetic tree begins with the line of Eukarya and then holds the species of the Archaea division, which includes those prokaryotic organisms that live in extremely harsh environmental conditions ( such as Methanobacterium, and extreme halophiles).
As this last branch holds species of two domains ( from 3 domain system of classification that includes Bacteria, Archaea, and Eukarya) , which are Archaea and Eukarya as it begins with Eukarya and later on holds the species of Archaea.
Thus, it shows that Archaea and Eukarya are more genetically related.