Which of the following is a heterotrophic eukaryote associated with the decomposition of dead organisms

hi i’m going crazy about going tomorrow and i’ll tell you what i’m doing and i wanna is a way ya

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands

thinking it would be d not too sure but i think it's right