Final answer:
Amelia's behavior best illustrates altruism, which is selfless helping of others regardless of personal costs.
Step-by-step explanation:
Amelia's behavior of helping her family members and friends with the ultimate goal of benefiting them, even if it incurs a cost to herself, best illustrates altruism. Altruism is a form of prosocial behavior that is motivated by selfless helping of others, regardless of personal costs. In the case of Amelia, she prioritizes the well-being of others over her own.