Answer:
The correct answer is - placebo-controlled.
Explanation:
A placebo-controlled group is a group of individual that receives an inactive medicine or substance, placebo, to prove research while other groups get real medication or medical therapy.
Placebo-controlled studies are related to test medical therapy. It is developed especially to have no effect and just to create a placebo effect.
Thus, the correct answer is - the placebo-controlled.
