Since 1975 advocates of humane treatment of animals have broadened their goals to oppose the use of animals for fur, leather, wool, and food. They have mounted protests against all forms of hunting and the trapping of animals in the wild. And they have joined environmentalists in urging protection of natural habitats from commercial or residential development. The occasion for these added emphases was the publication in 1975 of "Animal Liberation: A New Ethics for Our Treatment of Animals" by Peter Singer, formerly a professor of philosophy at Oxford University in England.
This book gave a new impetus to the animal rights movement. The post-1975 animal rights activists arc far more vocal than their predecessors, and the organizations to which they belong arc generally more radical. Many new organizations arc formed. The tactics of the activists arc designed to catch the attention of the public. Since the mid-1980s there have been frequent news reports about animal right organizations picketing stores that sell furs, harassing hunters in the wild, or breaking into laboratories to free animals. Some of the more extreme organizations advocate the use of assault, armed terrorism, and death threats to make their point. Aside from making isolated attacks on people who wear fur coats or trying to prevent hunters from killing animals, most of the organizations have directed their tactics at institutions. The results of the protests and other tactics have been mixed. Companies arc reducing reliance on animal testing. Medical research has been somewhat curtailed by legal restrictions and the reluctance of younger workers to use animals in research. New tests have been developed to replace the use of animals. Some well-known designers have stopped using fur. While the general public tends to agree that animals should be treated humanely, most people arc unlikely to give up eating meat or wearing goods made from leather and wool. Giving up genuine fur has become less of a problem since fibers used to make fake fur such as the Japanese invention Kanecaron can look almost identical to real fur. Some of the strongest opposition to the animal rights movement has come from hunters and their organizations. But animal rights activists have succeeded in marshaling public opinion to press for state restrictions on hunting in several parts of the nation.
1975 was an important year in the history of animal treatment because ______.

A. many people began to call for humane treatment of animals that year
B. a new book was published that broadened the animal rights movement
C. the environmentalists began to show interest in animal protection
D. the trapping of animals began to go wild all through the world