单选题
Personality is to a large extent inherent—A-type parents usually bring about A-type offspring. But the environment must also have a profound effect, since if competition is important to the parents, it is likely to become a major factor in the lives of their children. One place where children soak up A-characteristics is school, which is, by its very nature, a highly competitive institution. Too many schools adopt "the win at all costs" moral standard and measure their success by sporting achievements. The current passion for making children compete against their classmates or against the clock produces a two-layer system, in which competitive A-types seem in some way better than their B-type fellows. Being too keen to win can have dangerous consequences: remember that Pheidippides, the first marathon runner, dropped dead seconds after saying: "Rejoice, we conquer!" By far the worst form of competition in schools is the disproportionate emphasis on examinations. It is a rare school that allows pupils to concentrate on those things they do well. The merits of competition by examination are somewhat questionable, but competition in the certain knowledge of failure is positively harmful. Obviously, it is neither practical nor desirable that all A-youngsters change into B's. The world needs A-types, and schools have an important duty to try to fit a child's personality to his possible future employment. It is top management. If the preoccupation of schools with academic work was lessened, more time might be spent teaching children surer values. Perhaps selection for the caring professions, especially medicine could be made less by good grades in chemistry and more by such considerations as sensitivity and sympathy. It is surely a mistake to choose our doctors exclusively from A-type stock. B's are important and should be encouraged.
单选题
According to the passage, A-type individuals are usually______.