The correct option is D all of the above
Phylogenetic classification which involves the evolution of an organism gives a complete method of classification. But the possibility of having an ideal evolutionary classification is not possible as we may see an organism having both primitive and advanced traits. A good example of this is the presence of vestigial organs. Also, evolution has not taken place only in one direction but in many directions like branches of a tree. Innumerable differences in the evolutionary trends of plants have been identified and variations occur in different degrees in different forms of a character. Evolution of amphibians, reptiles and also aves have been linked. The phylogenetic system is a dynamic system and its major sources are the fossil records. Many times a fossil linking two groups may not have been discovered which can lead to problems in exploring the full fossil ancestry of an organism.