D. "It is for this reason that I wish to introduce today a proposal that has been before every Congress for the last 40 years."
Explanation:
The sentence from the options that exemplifies the use of formal language by the congresswoman is the last option, since it uses phrases like "It is for this reason" which in a less formal or more casual language should be expressed as "because of this", and in this sentece the congresswoman is trying to express the introduction of a proposal.
The answer is option D: "It is for this reason that I wish to introduce today a proposal that has been before every Congress for the last 40 years."
The statement best exemplifies the use of formal language because, to begin with, it is a complex sentence. In fact, it is a cleft sentence which begins with <em>it </em>to emphasize what comes next. Secondly, there is no ellipsis and vocabulary reflects the choice of longerwords than in informal speech. Finally, the use of passive voice is typical of formal registers.
