Task: Question Answering
Input (English): Question: In a clinical study to evaluate the efficacy of a new medication in the treatment of migraine crisis (point out the CORRECT): 
 Options:  <1> Strict inclusion criteria increase the external validity of the study. <2> Strict exclusion criteria reduce the internal validity of the study. <3> Control with a placebo arm increases the external validity of the study. <4> Masking reduces the internal validity of the study. <5> Randomization increases the internal validity of the study.
Output (English): 5