A、Food packaging. B、Varieties of fish. C、A new snack food. D、An artificial food flavoring. C①四个选项都是名词词组，且是此篇对话的第一题，由此可以判断很可能是主旨题

W: I’ve been reading about a new healthy snack food. It’s made from fish. Have you heard anything about it?
M: No, I haven’t But I don’t like fish very much anyway.
W: Not to worry. Although it’s made primarily from fish, it actually doesn’t have a fishy taste. In fact, it can be flavored with tomato, cheese, or chocolate for instance.
M: How could it not taste fishy? Do you know how this snack food is made?
W: First, the fish is minced, cooked and fermented, then water and starch are added to make a dough.
M: It sounds awful.
W: Actually the dough is very dull at that point[2]So the flavorings are added to give it some flavor.
M: Well, it still sounds a little strange. But I suppose this product will at least be low calorie and high protein, like a health food.
W: Yes, you could call it that. And it has a long shelf life, so it won’t spoil quickly. It is also easy to digest and can be made from types of fish that usually aren’t eaten or from high grade fish by-products.
M: Mh... Have you got any samples? I might be willing to try the cheese-flavored variety.
W: No. None of these seem to be available yet As I understand it, this fish snack food probably won’t be in the stores for another couple of years. So you have a while to get used to the whole idea.
M: A couple of years, ha? It may just take me that long, but thanks for telling me about it.
1 What is the main topic of the conversation?
2 Why are flavorings, added to the dough?
3 What would be a good reason for buying the product?
4 Why isn’t any sample available?