Which of the Following Was NOT Mentioned in the Textbook

Multiple Choice

Which of the following was NOT mentioned in the textbook as a limitation of observational data?

A) Normally only a small number of subjects are studied.
B) Recall error is maximized.
C) Subjective interpretation of results is required on the part of the researcher.
D) Underlying motives are left unexamined.
E) Underlying attitudes are left unexamined.