Cole Was Involved in a Research Study to Find Out

Multiple Choice

Cole was involved in a research study to find out if a particular medicine was safe and could help prevent meningococcal disease in healthy teenagers.Some of the study participants received a shot with no medicine in it (a placebo) ,while other participants received a shot containing the medicine.Neither the doctor nor Cole would know what shots were being administered or whether Cole was in the experimental or control group.This type of study is known as a(n) :

A) experimental study.
B) double-blind study.
C) placebo study.
D) case study.