A Researcher Interested in "Inattentional Blindness" Has a Confederate Walk

Multiple Choice

A researcher interested in "inattentional blindness" has a confederate walk across a stage holding a large sign during the first class of an introductory psychology course.At the end of the class,assistants ask departing students if they know what the sign said.This is an example of

A) structured observation.
B) a field experiment.
C) qualitative research.
D) undisguised participant observation.