A、Oil. B、Wood. C、Natural gas. D、Coal. B

W: Everyone seems to be talking about climate change these days!
M: I’m not surprised. It’s all these greenhouse gases--that’s what’s causing the problem!
W: What are the greenhouse gases?
M: You know, carbon dioxide, which comes mainly from the burning of fossil fuels, such as oil, gas and coal.
W: I’ve never understood why that’s a problem.
M: Evidently these gases build up in the earth’s atmosphere, and trap the heat from the sun.
W: And so this heat is warming the planet?
M: Exactly!
W: Well, isn’t that good news? I hate these cold winters we get!
M: Yes. But what’s good for you here may not be so good for people elsewhere in the world. For the average world temperatures could rise. That can have a huge effect on local climates and ecosystems around the world,
W: So you really think that these floods we’ve seen m the news could be caused by global warming?
M: Sure! And also the droughts and the storms.
W: So what can we do about it?
M: It’s not realistic to stop using fossil fuels today. But we can start trying to reduce carbon dioxide emissions.
W: And look for alternative sources of energy too, of course!