If you are asked to submit a sample writing, make sure you submit something high quality. This is perhaps the most important part of your application because it showcases your academic abilities more than anything else. Bachelor’s and Master’s theses as well as advanced course papers are good for this. What matters is the quality of the work. It is good to start this process a year earlier (fall of the third year) and get several rounds of comments on your drafts before submitting.
You can email us your sample writing and get feedback on the quality of your work.