Social science is often hampered by the fact that people are hesitant to discuss their beliefs for fear of ridicule. This is the case in research on folk medical practices, particularly when the subjects know that society in general and health care professionals in particular devalue such folk practices. Practitioners of folk medicine are often less than eager to share their knowledge, in part because they wish to avoid exploitation of their knowledge and in part for fear of criticism. According to this paragraph, which one of the following statements is true:

a. research has found that folk medicine is harmful to one's health. b. the element of fear can hinder social science research. c. social science considers folk medicine of too little value to research. d. people won't discuss folk medical practices because they are illegal.