Which of the Following Is True of Key Informants as a Means

Which of the following is true of key informants as a means to measuring substance-abuse-related needs?

A) Their subjective opinions can never replace objective data.
B) Their widely generalized accounts often lead to a lack of focus in the assessment.
C) Their objective views often make surveys and open forums redundant.
D) Their accounts are too specific and thus often miss the larger picture of the problem.