Answer:
C. developmental psychologist; personality psychologist
Step-by-step explanation:
Actually, since Dr. Chen studies how people grow and change during late adolescence and young adulthood, he is a developmental psychologist. Developmental psychology is the study which focuses on the changes and growth that occur in humans during the course of their life. It is usually concerned with development that occur in infants, adolescents, adult development and even aging. One who carries out such study is known as a developmental psychologist. Therefore, Dr. Chen is a developmental psychologist.
Also, since Dr. Doherty focuses on several traits that distinguish one person from another, he is known as a personality psychologist. Personality psychology is the study of the personality of individuals and how they vary among such individuals. One who carries out personality psychology is known as a personality psychologist. Therefore, Dr. Doherty is a personality psychologist.