A medicine to remove the redness in eyes was tested in a group of 100 students. Each student took either the medicine or a placebo in both eyes. The specific treatment for each student was decided by flipping a coin. The participants in the study did not know if heads or tails resulted in the medication. For each of the following basic principles of statistical design, indicate if it was used in this experiment (yes) or not (no).

A) Control
B) Randomization
C) Repetition
D) Blinding