When Asking Questionnaire Items, the Interviewer Should​

When asking questionnaire items, the interviewer should​

A) ​ask every question even if the respondent has apparently answered it already.
B) skip questions that the respondent cannot answer and return to them at the end of the interview.​
C) react to a question after the respondent has answered to show interest​
D) give help on difficult questions.​
E) ​summarize the respondent's answers so that they are more meaningful answers.