Rogers said it is difficult for a therapist to know a client's experiential world completely,because

A) no form of therapy is infallible.
B) communication is never perfect.
C) non-conscious experiences are inaccessible.
D) all of these are correct.

Rogers emphasized the subjective and personal nature of an individual's experience, acknowledging that communication limitations, the fallibility of therapeutic approaches, and the inaccessibility of non-conscious experiences all contribute to the difficulty therapists face in fully understanding a client's experiential world.