Final answer:
Marcia and Erikson assumed that identity formation is a conscious process in adolescence, where individuals actively explore and experiment to establish their sense of self. So, the correct answer is option c.
Step-by-step explanation:
In adolescence, the main task for individuals is to develop a sense of self, which includes forming their identity. Marcia and Erikson assumed that identity formation is a conscious process and that adolescents go through a period of exploration and experimentation to find their true identity. This means that identity formation is not predetermined or solely determined by genetics. It is a process that individuals actively engage in to establish their own sense of self.
So, the correct answer is option c.