Final answer:
The correct answer is option D. Conformist Stage.
Step-by-step explanation:
Taking into consideration the preoccupation with social acceptance, appearance, and material possessions, the child is most likely at the Conformist Stage of ego development. At this stage, individuals are typically concerned with fitting in and are attentive to the expectations and norms set by society and peers. They may often alter their preferences or behavior to align with group standards, which is common during the developmental stage of adolescence as described by Erikson's theory.
The main task of adolescence in Erikson's theory of psychosocial development is identity formation, where teens internalize messages about their strengths and weaknesses and work towards establishing their own identity. This involves assessing and integrating their experiences and the perceptions of others, which can heavily influence their self-concept and confidence.
In contrast, the Autonomous Stage is characterized by independence and self-regulation, and the Integrated Stage by a full acceptance of oneself and others despite conflicts or differences. Therefore, given the description provided, D. Conformist Stage most accurately describes the ego development sequence for the child in question.