What Significant Methodological Difficulty Is a Weakness of Self-Report Studies

What significant methodological difficulty is a weakness of self-report studies to determine the validity of differential association theory?

A) Subjects experience memory failure.
B) It is difficult to determine whether differential associations were the cause or the result of crime.
C) It is difficult to get parents to discuss their criminality.
D) Differential associations involve social interactions, which are always difficult to determine.