Which of the Following Is TRUE

Which of the following is TRUE?

A) A double-barreled question is one that calls for two responses and thereby creates confusion for the respondent.
B) It is extremely important that the first few questions on a questionnaire be simple,interesting,and in no way threatening to the respondents.
C) Opinion questions are typically good openers for a questionnaire because people like to feel their opinion is important.
D) Both a and b.
E) a,b,and c.