The Interviewer is looking for a yes or no answer AND examples to support your answer.
If your answer is yes, indicate how often you are accustomed to multi-tasking at work. Maybe it was a daily need in your last role, or maybe it is something you've done once or twice. You can provide more general examples of times you may have to multi-task if you have used this skill regularly at work. If you have only used this skill once or twice, it will be much more impactful to provide a specific example.
If you haven't used this skill at work, consider a time you used it at home or indicate that you can learn how to multitask.