Final answer:
Hominins refer to the group that includes modern humans, extinct human species, and all immediate ancestors like Homo, Australopithecus, among others. The correct answer to the question is b) human species, as hominins are species closely related to humans.
Step-by-step explanation:
The term hominin refers to a group that represents modern humans, extinct human species, and all of our immediate ancestors. This classification includes the genera Homo, Australopithecus, Paranthropus, and Ardipithecus, categorizing species that are more closely related to humans than to chimpanzees, based on shared characteristics like bipedal locomotion. When considering the options presented in the question, hominin (a) apes and humans, b) human species, c) tarsiers, d) ceboidea, the correct answer is b) human species, as it encompasses all species in the direct lineage to humans, both modern and extinct.