Concept: A learning curve is a graph that shows how learning improves or progresses over time. Explanation: It is drawn with time or trials on the x‑axis and performance on the y‑axis. The curve rises as the learner gains skill and knowledge. Initially, learning is slow (stage‑1), then speeds up (stage‑2), and finally plateaus (stage‑3). The curve objectively measures progress in learning. Therefore, a learning curve indicates the rate and direction of learning progress. Answer: A. Progress in learning