Final answer:
The correct answer is C) finished.
Step-by-step explanation:
The correct answer is C) finished. It is the past tense form of the verb 'finish'. The sentence 'Have you finished your work?' is in the present perfect tense and is asking if the person has completed their work up until the present moment. 'Finished' is the correct form of the verb to use in this context.
For example, if someone asks 'Have you finished your homework?', they are asking if you have completed your homework at any point leading up to the present moment. If you say 'Yes, I finished it yesterday', you are indicating that you completed your homework in the past, specifically yesterday.
The other options, 'finish', 'finishes', and 'had finished', are either incorrect verb forms or indicate a different tense than the one needed in this question.