Psychologists were the specialist who study the behaviors and traits of individuals. The validation argued by the Psychologists is the validity of projective tests.
The projective tests are the diagnostic methods used by psychologists to study the behavior of the individual and his traits with the response to external stimuli.
The validation of the test is subjected to debate as it was considered as the varying parameter from person to person that made it non-validated. Thus, option D is correct.
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