What's the correct answer statistics

You've developed a new anxiety reduction treatment. Your study design is to separate a random sample of teens aged 16-19 from adults aged 20-35 into two groups, randomly divide each group in half, and then give one half the new medication and one half a placebo. The basic design of this study is: comparative randomized, blocked by gender. completely randomized. randomized, blocked by gender and type of medication. comparative randomized, blocked by age group None of the above