How did Greg start fire-walking?

Listen to the conversation, mark each question as A, B, C or D according to your listening.
W: So, Greg, this is certainly one of the most unusual hobbies I’ve heard of. How did it all start?
M: It was in 1977 that I first fire-walked. I was taught by a friend, and was so transformed by the experience, I immediately wanted to share it with as many people as possible. I wondered why no one was teaching fire-walking to the general public, and felt it was a valuable service needing to be offered. For almost seven years, I was the only person on the planet teaching fire-walking classes.
W: And have you had any problems teaching it?
M: It’s not an easy thing to do, and I should mention that I made many mistakes in those early years, and several dozen people were badly burned.
W: What kind of mistakes?
M: I used to make the coal beds six to eight inches deep. I soon learned that it was not the amount of coal, or the length of the fire-walk, which created the resulting exuberance and exhilaration people experienced, but rather, it was simply the act of taking one step—one step into an inferno ! Once I realised I could create the same results using safer fire pits which were less deep and much shorter in length, my injury rate dropped to almost zero.
W: That’s reassuring—almost zero! And why do you think people don’t get injured?
M: In 1978, I began seriously researching fire-walking, and discovered that there really was no definitive theory about the phenomenon. Every published theory contradicted some other published theory. No one could agree on why fire-walkers were not harmed by the glowing, red-hot embers. It then seemed to me that the best way to research fire-walking was to persuade as many people as possible to do it, so as to accumulate a large group that could be observed and studied. Therefore, I took it upon myself to create such a group. It became my personal mission. No one before me had ever embarked on a crusade to convince as many people as possible to step into fire pits containing red-hot coals exceeding 1 ,200 degrees Fahrenheit.
W: So, you’re still doing it?
M: Yes, all the time. Care to join my group?
W: I don’t think so, thanks. I value my feet!