Which description is required to justify the number of subjects enrolled?

• A. The number of subjects planned to be enrolled
• B. The color of the data capture forms
• C. The site facility layout
• D. The post-trial access plan

Answer: (A)

Sample size is justified by the plan for how many participants will be enrolled, because the study must show it has enough power to detect a meaningful effect. The protocol should state the exact number planned and the rationale behind it, typically based on power calculations, anticipated effect size, data variability, desired significance level, and expected dropout. This description directly supports why that enrollment target is appropriate and feasible. Other aspects like the color of data capture forms, the site facility layout, or a post-trial access plan do not influence how many subjects are needed and thus do not describe the basis for the enrollment number.