Which of the Following Is a Disadvantage of Self-Administered Questionnaires

Which of the following is a disadvantage of self-administered questionnaires?

A) They have higher administrative costs than telephone surveys.
B) Detailed,in-depth questions cannot be asked in a self-administered questionnaire format.
C) Researchers are unable to provide clarification or answer the questions of the respondent.
D) Self-administered questionnaires are only useful for people who lack strong literacy skills.