Phase classification is based on study objectives, not just subject numbers.
* Phase I:Focuses on safety, pharmacokinetics, dose-ranging, usually in healthy volunteers or small patient groups.
* Phase II:Evaluateseffectiveness in patients with the conditionand monitors common short-term side effects.
* Phase III:Confirms effectiveness in larger populations, compares to standard therapy, gathers more safety data.
* Phase IV:Post-marketing studies exploring new indications, long-term safety, or special populations.
The given study aims toevaluate effectiveness and common short-term side effectsin 30 arthritis patients, which clearly aligns withPhase IIobjectives. It is not exploratory safety (Phase I), not confirmatory comparative (Phase III), nor post-marketing (Phase IV).
Thus, the correct answer isB (Phase II).
References:
FDA Guidance: The IND Application - §312.21 (Phases of an investigation).
ICH E8(R1), General Considerations for Clinical Studies.