Final answer:
The first hominin species to exhibit care-giving behavior for the elderly and infirm is Homo erectus, as evidenced by archaeological findings indicating support for individuals with long-term illnesses.
Step-by-step explanation:
The first hominin species to demonstrate caring behaviors for the elderly and infirm, where individuals were assisted by other members of the group, was Homo erectus. This evidence is seen in the discovery of remains of individuals who had long-term debilitating diseases, yet survived for extended periods due to the support from others within the group. Homo erectus not only walked upright but also displayed advancements in tool-making, fire use, and possibly a primitive form of vocal communication which would have facilitated care-giving behaviors. Unlike Australopithecus Africanus which preceded Homo erectus, there isn't strong evidence to suggest the same level of societal care.
Therefore, the answer to the student's question is option C: Homo Erectus.