According to Your Textbook, the Main Reason That We Do

According to your textbook, the main reason that we do not have sufficient research examining the development of personality disorders is that

A) many individuals do not seek treatment in the early phases of these disorders.
B) there is insufficient research funding for these disorders due to relative lack of public awareness.
C) sophisticated research methods are necessary to study disorders that are so ingrained in personality.
D) all of these are correct.