Recall that we're looking for the main point of the argument in the stimulus. "Such a position ignores the lessons of experience" is the main point in this stimulus, as the rest of the stimulus is used to support this phrase. The argument concludes that legislators are ignoring the lessons of history. We need to look for this in the correct answer choice.
(E) says, "Lack of guarantees that new scientific research will contribute to the public welfare is not sufficient reason for legislators to refuse to commit public funds to new scientific research."
(E) looks great, as it's a paraphrasing of the conclusion we identified. Refusing to commit funds to research based on a lack of demonstrated benefit ignores the lessons of experience. Thus, (E) is the correct answer choice.
Does this make sense? Let us know if you have any other questions!