Final answer:
Children are the least likely to exhibit post-conventional reasoning as they typically operate within the pre-conventional level, which is focused on direct consequences and egocentric perspectives. Adolescents, adults, and the elderly are much further along in their cognitive and moral development, making children the least developed in this respect.
Step-by-step explanation:
When it comes to post-conventional reasoning, which is the final stage of Lawrence Kohlberg's theory of moral development, it involves a higher level of cognitive ability where morality is thought of in abstract terms. According to Kohlberg, individuals usually progress through the stages of moral reasoning, starting with pre-conventional morality, moving to conventional morality, and lastly, to post-conventional morality. This final stage includes the recognition that legality and morality do not always match, and it embodies the principles of justice and rights beyond individual societies
Considering this progression, Children are less likely to exhibit post-conventional reasoning, since they typically operate at a pre-conventional level due to their cognitive development being focused on direct consequences and a more egocentric view of the world. Adolescents develop conventional reasoning, where conformity to societal norms becomes important, but they may lack the full mature abstract thinking required for post-conventional reasoning. While adults and the elderly are more likely to have reached the ability for abstract thinking, it is nonetheless true that not all individuals reach post-conventional reasoning even later in life. Events and personal experiences play a significant role in one's advancement to this stage.
Thus, within the options given, Children are the category that is least likely to exhibit post-conventional reasoning because they have not yet reached the required stage of cognitive and moral development.