Final answer:
According to Lawrence Kohlberg's theory of moral development, the person at the conventional level of personal moral development would be C. Gary, as he follows rules and performs well to avoid punishments.
Step-by-step explanation:
According to Lawrence Kohlberg's theory of moral development, the conventional level involves individuals considering what society considers moral and immoral. This level is characterized by an emphasis on following rules and performing well to avoid punishments, as well as a concern for self and others. Therefore, among the given options, the person at the conventional level of personal moral development would be C. Gary, as he follows rules and performs well to avoid punishments.