An environmental research group, using the fixed-alternative format, surveys people about their re-cycling practices in order to determine support for a ban on non-returnable bottles. The group does not reveal itself or its stance on the issue. The format of this questionnaire is best described as

A) structured-disguised.

B) unstructured-disguised.

C) structured-undisguised.

D) unstructured-undisguised.

E) unstructured-open ended.