Social adjustment is to determine the behavior of the subject of social life through a certain social authority, indicate its role and development direction, and purposefully incorporate it into a certain order. Social adjustment can be divided into internal adjustment and external adjustment according to the way it acts on people's behavior and the reasons why people obey it. Internal adjustment is the process of people learning the behavioral regulations of a certain social group, while external adjustment is the process of making people abide by certain social norms through external pressure.
According to the above definition, which of the followings belongs to internal adjustment?
Under the education of his parents, 3-year-old Xiao Ming knew when crossing the road, he had to walk on the zebra crossing.