You plan a trial testing a new flavored nutritional beverage. To choose the best control, which is most appropriate?

Assign control participants to an unrelated exercise program so they feel engaged while the treatment arm receives the beverage, avoiding the need for blinding

No control at all; give everyone the new beverage and compare outcomes to historical norms from other studies, which avoids participant inconvenience

A visually and taste-matched placebo beverage without the active ingredient, with participants randomized to beverage A or placebo to isolate the active ingredient’s effect

Use a control beverage that differs in both taste and appearance to make it obvious who is getting the active product, because transparency increases compliance