Problem:
What is the "chief" advantage (best method) of using each of the following contact methods: mail questionnaire, telephone interview, and personal interview?
Please note that (1) all references including in-text citation should be cited accoding to APA guidelines; and (2) one of the reference sources should be the book "Marketing Management (14 edition)" wrote by Philip Kotler and Kevin Lane Keller, published by Pearson Education, US in 2012.