input: The following are multiple choice questions (with answers) about medical knowledge.   **Question:** Which of these is not true about randomization in a clinical trial?   (A) Reduces confounding   (B) Decreases selection bias   (C) Ensures comparability of two groups   (D) Increases external validity of the trial
output: ['(D) Increases external validity of the trial <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Reduces confounding  (B) Decreases selection bias  (C) Ensures comparability of two groups  (D) Increases external validity of the trial <> possible answers', '  Which of these is not true about randomization in a clinical trial? <> context']