Indicate Whether the Study Described Is an Observational Study or a Controlled

Multiple Choice

Indicate whether the study described is an observational study or a controlled experiment.
-A group of students is divided into two groups. One group is a given a new chewable vitamin and the other group is given a placebo. After six months they are asked to fill out a questionnaire and given a health exam to see whether the new vitamin has health benefits that are better than a
Placebo.

A) Controlled experiment
B) Observational study