[单选题]
2. Which of the following can be used to classi5my4h5;5 0v iv lsorndfy organaanenagge 7hcc;rd vo08+2+1 isms into clades?
I. Common ancestry.
II. Shared morphological characteristics.
III. DNA base sequences.
IV. Chromosome number.
A. All of the above
B. IV only
C. I, II and III only
D. I, III and IV only