There are several ways of addressing this one. You may be the sort of person that works well under pressure; you may even thrive under pressure. Whatever the case, make sure you don't say you panic. You want to give specific examples of stressful situations and how well you dealt with them. You may also want to list a few tools you use to help you, such as to-do lists, etc. It is alright to say that you will ask for assistance when the job is more than what you can handle. It is equally acceptable to say that you work best under pressure if this is indeed the case and relevant to the particular role.