The correct answer is D. Experienced teachers can equip themselves with a brief outline as they gain specialization in it through experience.
Option A is incorrect because experienced teachers may still need a detailed lesson plan to ensure that they cover all of the important points.
Option B is incorrect because the number of curious students in a class is not necessarily related to whether or not an experienced teacher needs a detailed lesson plan.
Option C is incorrect because experienced teachers may still face challenges from their students, even if they do not make mistakes.
Option D is the correct answer because experienced teachers can use their experience to develop a brief outline that covers the most important points of a topic. This allows them to be flexible and adapt their teaching to the needs of their students.