Kathy Jenkins is planning to conduct research on consumers' personal care routines. Since the questions are likely to be personal and sensitive, Kathy wants to select a contact method that will encourage respondents to answer honestly. Which of the following contact methods is most likely to best serve Kathy's purpose?

Mail questionnaire: In research, the term mail questionnaire is defined as a form or type of questionnaire that is being mailed by the researcher to the targeted persons or group, that possesses a specific collection of questions on a few specific topic being asked to them and determined as a part of the survey or interview which is used for researching on that particular topic.

Advantage: Anonymity and confidentiality.

In the question above, Kathy's purpose is being best served by a mail questionnaire.