Answer:
post-conventional level
Step-by-step explanation:
Kohlberg's Stages of Moral Development have been categorized into three stages and each stage is further divided into two sub-stages. The post-conventional stage is the third stage of moral development which is characterized by the principle of abstract reasoning and moral logic which are based on individual conception of justice even if they differ from prescribed rules. As per the question, lifeguard chooses to act on his internalized principle which reflects post-conventional level of morality.