Answer:
Concrete; more abstract and complex.
Step-by-step explanation:
Psychology may be defined as the branch of science that mainly deals with the behavior, understanding and mental situation of the individual. The psychologist who is expertise in the field of psychology.
The psychologist studies different methods and concept in psychology. The concept of the self start of an individual is generally concrete and quite complex. But later on this concept becomes more complex and more abstract is included in this stage.
Thus, the correct answer is option (b).