Concept:The plateau in a learning curve refers to a period of no apparent improvement; it is commonly caused by fatigue or boredom from repetitive practice.Explanation:The learning curve has three main stages: slow beginning, steep progress, and plateau. In the plateau stage, learners have already mastered the concept and may feel bored or tired due to repetition. This lack of new challenge leads to mental or physical fatigue, which halts further improvement. Therefore, among the given options, fatigue (option C) is the primary cause of a plateau.
