Which of the following is NOT an example of an open-ended question?

a. "What are your thoughts on this most recent form of legislation?"
b. "How did you become an environmental activist?"
c. "How long have you been working in the healthcare industry?"
d. "Why do you believe raising tuition rates is the best to offset budget cuts?"

c. Open-ended questions do not restrict the form or content of an answer, and they
allow interviewees to offer information voluntarily.