A、Because they are important for the balance of ecosystem. B、Because parts of them can be made into delicious food. C、Because so

Many people think Shark is one of nature’s fiercest creatures. Some people,however,do not approve of catching sharks. They do not think all sharks are terrifying enemies. (26) Activists for sharks note that the fish are valuable in the ocean. Sharks eat injured and diseased fish. Their hunting means that other fish do not become too great in number. This protects other creatures and plants in the ocean. Environmental activists worry that some kinds of fish are in danger of dying out. It is estimated that fishing operations kill more than one hundred million sharks every year.
    The number of shark attacks has, in fact, decreased in recent years. During this period, there was an average of 63 attacks worldwide each year. That compares with a high of 79 in 2000.
    Shark attacks are either provoked or unprovoked. An unprovoked attack means the person must not have interfered with the shark. Some divers interfere with sharks on purpose. They want to get the attention of sharks,perhaps to take pictures of them. (27) The diver may put food in the water to get the animal to come close. Sharks do not normally want to be with people. But their excellent sense of smell leads them to food. Some divers,filmmakers and nature photographers enter a shark’s territory with inside containers made of steel. Others wear heavy metal equipment for protection. And others get near sharks wearing only normal diving equipment. Close contact with sharks has its critics. Some people say it represents invasion of the animals’ territory for no good reason. (28) But exciting films may increase public interest and sympathy for the animals.
26. Why do activists for sharks say sharks are valuable?
27. How do divers attract sharks coming close?
28. According to the passage, what reason justifies people’s interference with sharks?