There are many sources of data that can be used in a qualitative case study. Common sources are questionnaires with open-ended questions, one-on-one semi-structured interviews, focus groups, and archival data. You have been asked to conduct a qualitative case study of high school teachers to explore their thoughts and perceptions about the use of tablets in the classroom. Which of the above sources would be the best sources of data to conduct this research as a qualitative case study? Why? Which of these data sources would be less useful for a qualitative case study design? Why?