What Was the Major Conclusion Drawn by Rosenham (1973)on the Research

What was the major conclusion drawn by Rosenham (1973) on the research involving the hospitalization of pseudo-patients?

A) All pseudo-patients were correctly identified by hospital staff.
B) None of the pseudo-patients were correctly identified by hospital staff.
C) About half the pseudo-patients were correctly identified by hospital staff.
D) Pseudo-patients came to internalize their symptoms to such an extent that their condition progressively worsened during their hospital stay.
E) None of the above