【单选题】

Science Fiction can provide students interested in the future with a basic introduction to the concept of thinking about possible futures in a serious way, a sense of the emotional forces in their own culture that are affecting the shape the future may take, and a multitude of predictions regarding the results of present trends.

Although SF seems to take as its future social settings nothing more ambiguous than the current status quo or its totally evil variant, SF is actually a more important vehicle for speculative visions about macroscopic social change.At this level, it is hard to deal with any precision as to when general value changes or evolving social institutions might appear, but it is most important to think about the kinds of societies that could result from the rise of new forms of interaction, even if one cannot predict exactly when they might occur.
In performing this "what if ..." function, SF can act as a social laboratory as authors ruminate upon the forms social relationships could take if key variables in their own societies were different, and upon what new belief systems or mythologies could arise in the future to provide the basic rationalizations for human activities. If it is true that most people find it difficult to conceive of the ways in which their society, or human nature itself, could undergo fundamental changes, then SF of this type may provoke one’s imagination--to consider the diversity of paths potentially open to society.
Moreover, if SF is the laboratory of the imagination, its experiments are often of the kind that may significantly alter the subject matter even as they are being carried out. That is, SF has always had a certain cybernetic effect on society, as its visions emotionally engage the future--consciousness of the mass public regarding especially desirable and undesirable possibilities. The shape a society takes in the present is in part influenced by its image of the future; in this way particularly powerful SF images may become self-fulfilling or self-avoiding prophecies for society. For that matter, some individuals in recent years have even shaped their own life styles after appealing models provided by SF stories. The reincarnation and diffusion of SF futuristic images of alternative societies through the media of movies and television may have speeded up and augmented SF’s social feedback effects. Thus SF is not only change speculator but change agent, send an echo from the future that is becoming into the present that is sculpting it. This fact alone makes imperative in any education system the study of the kinds of works discussed in this section.
In discussing the subject matter of SF, the author focuses onA．its main functions.
B．its great diversity.
C．its bold assumptions.
D．its social impact.