5. Twenty volunteers with high cholesterol were selected for a trial to determine whether a new diet reduces cholesterol. The volunteers were given a low-carb,

low-calorie diet. After 8 weeks of the diet, the average cholesterol of the

volunteers dropped a significant amount. This study is an example of

(A) A controlled experiment.

(B) An uncontrolled experiment.

(C) A double blind experiment.

Ablocked design experiment.