Social mobility refers to the ability of individuals or groups to move between social classes. This movement can be upward (ascending to a higher social class) or downward (falling to a lower social class) and can occur due to various factors such as education, occupation, and economic changes.
Social integration (B) refers to the process of incorporating individuals into society, social cohesion (C) refers to the unity and bonds that hold society together, and social deviance (D) involves behaviors that violate societal norms. Therefore, social mobility is the correct term for class movement.