Final answer:
Descriptive feedback is more helpful earlier in the learning process while prescriptive feedback is more helpful later in the learning process.
Step-by-step explanation:
Descriptive feedback is more helpful earlier in learning because it helps learners understand what they are doing well and where they might improve. On the other hand, prescriptive feedback is more helpful later in the learning process, as it provides specific guidance on how to improve or correct errors. Therefore, the correct answer to the student's question is: Descriptive feedback is more helpful earlier; prescriptive feedback is more helpful later.