How many scientists did the man cite as examples to illustrate his point?

Listen to the conversation.
Then read the four choices marked A,  B,  C and D, and decide which is the best answer according to what you hear.
W: Can you tell us about what happens when geniuses relax?
M: Without doubt, great scientists don’t always make their discoveries in the lab. Archimedes’s famous ‘Eureka’ moment came while he was having a bath. Physicist Richard Feynman saw a plate flying through the air in a college cafeteria, and was inspired to calculate electron orbits. He later won the Nobel Prize. And Alexander Fleming was making mould for his hobby, microbe painting, when he accidentally developed penicillin.
W: So what does this tell us?
M: Well, we’re looking into the psychology of high achievers. A recent study by Robert Root Bernstein compared the hobbies of 134 Nobel Prize winning chemists with those of other scientists. He found that most Nobel Prize winners acquired their accomplishments outside the lab. Over half were artistic and almost all had a long-lasting hobby: chess or insect collecting. Twenty-five percent of the Nobel Prize winners played a musical instrument and 18 percent drew or painted regularly. Of the common scientists, under one percent had a hobby.
W: Fascinating. So should we conclude then, that only a creative person can be a genius?
M: Well, I think that’s debatable. Perhaps it’s true up to a point, but I don’t think it’s as clear-cut as that. What we do know is that to a certain extent, creative thinking can help people to solve problems, even scientific ones. If you’re thinking about a problem all the time, often the answer eludes you. But it may come in an inspiration when you’re least expecting it— perhaps when you’re asleep, or thinking about other things, doing a hobby, for example. It’s not 100 percent certain, but it seems that the mind has the ability to make connections from one part of your life to another, so that actually stepping back from a problem can often provide the answer. And people who’re good at making these connections, people who pursue creative hobbies and interests, often excel in their particular fields.