Volunteers in a Study Are Assigned Randomly to Groups

Multiple Choice

Volunteers in a study are assigned randomly to groups.Some of the volunteers receive an herbal supplement that is reputed to control nausea,and some of the volunteers are assigned to a control group where a placebo is administered.This is an example of a(n) :

A) longitudinal study.
B) RCT.
C) meta-analysis.
D) appraisal tool.