A model that uses DNA comparisons to see how long two different organisms have been evolving independently from each other is referred to as molecular clock. It makes use of a genetic material that go through mutation. This is used to calculate the time of evolution between two different organisms.
A phylogenetic tree is also called as evolutionary tree. It is a diagram used to illustrate the lines of evolutionary descent of various species from a common ancestor. A cladogram is is a diagram that illustrate the relationships of various froups of taxa.
Answer - A. molecular clock hypothesis