This was somewhat difficult for me to answer, as in my previous role, you didn't prioritize per se. As a Sales Support Coordinator for a very busy advertising company, prioritizing was a figment of my imagination. I worked in alignment with very demanding, and unforgiving spirits. Therefore, when I had multiple projects due for a deadline, I worked on them simultaneously. I had two monitors, two independent CPU's, and would work dual screens. I could very well have 4 applications running on one computer, while 3 ran on the other. This is my idea of prioritizing. You didn't, you simply got things done as they were assigned or requested. I had a hard time explaining this while in the moment, and as a result, I feel my interviewers had a hard time conceptualizing it.