At age three, Bonnie realizes she is female and she wants to become skilled at being a girl. She begins to watch her mother and older sister and to model her behaviors aftertheirs. Bonnie's efforts to learn how to act feminine are best explained by which theory?

Social learning.

Explanation:

Albert Bandura propounded the social learning theory which was a pioneering work in the field. According to him, learning is fostered by the observation and modeling. His famous experiment called Bobo Doll experiments explained how children learn just observing the behavior of others. As per the question, Bonnie learns just from observing her mother and sister and therefore a classic example of social learning.