57. Joplin’s 5-stage model was created to be intentionally simple and define learning but isnot a learning theory itself. The model is organized around a “hurricane-like cycle”emphasizing a challenging action in between focusing and debriefing. These“action-reflection” cycles are differentiated from experience alone by incorporating areflection process. The application of the cycles can be in either a “maxi” or “mini”scope, depending on the intent of the project； the cycle can focus on large-scale coursedesign or a brief teaching moment or insight. Which stage of Joplin’s model ofexperiential learning is characterized by “challenge”?
(A) focus
(B) action
(C) feedback
(D) debrief