A、A CD player. B、A Cassette player. C、An MP3. D、An MP4. BWhat kind of player often produces a hiss sound while playing?

W: You went to the Grand Concert Hall yesterday?
M: Yes. It was really fantastic.
W: You are crazy about music, aren’t you?
M: Yes, I am. It is always my favorite.
W: What type of music do you like most?
M: I enjoy listening to all kinds of music—classical, jazz, rock and roll...but my favorite is pop music.
W: I like pop music, too. But my favorite is still country music.
M: Country music? Then you must know John Denver and his songs.
W: That’s right. I’m familiar with all his songs. I like "Country road takes me home" most. Unfortunately, my cassette-tape recorder broke down the other day.
M: Oh, have you thought of buying a new one? Or buying a CD player instead?
W: I’ve no idea. I don’t know which I should choose.
M: A Walkman is easier to carry, but the quality of the sound is not as good as that of a CD player. A cassette often produces annoying "hiss" sounds while playing. This is the reason why I myself chose a CD.
W: I have a question. Nowadays, many digital products like MP3 and MP4 have appeared on the market. Will they replace CDs completely and make them outdated?
M: It is hard to say. You’d better find more information about all these products before making a final decision.