问题如下：
A beneficial opportunity created by the derivatives market is the ability to:
选项：
A.adjust risk exposures to desired levels.
B.generate returns proportional to movements in the underlying.
C.simultaneously take long positions in multiple highly liquid fixed- income securities.
解释：
A is correct. Derivatives allow market participants to practice more effective risk management, a process by which an organization, or individual, defines the level of risk it wishes to take, measures the level of risk it is taking, and adjusts the latter to equal the former. B is incorrect because derivatives are characterized by a relatively high degree of leverage, meaning that participants in derivatives transactions usually have to invest only a small amount, as opposed to a large amount, of their own capital relative to the value of the underlying. This allows participants to generate returns that are disproportional, as opposed to proportional, to movements in the underlying. C is incorrect because derivatives are not needed to copy strategies that can be implemented with the underlying on a standalone basis. Rather, derivatives can be used to create strategies that cannot be implemented with the underlying alone. Simultaneously taking long positions in multiple highly liquid fixed- income securities is a strategy that can be implemented with the underlying securities on a standalone basis.
请问A是什么意思，如何翻译？另外怎么能达到期望水平呢？不是说远期F0（90）不会等于S90么
