The answer is D: A magazine article describing how people's lives have been improved by products developed as a result of the space program.
The most compelling piece of evidence is to show —like the article of the magazine does, which would have to be founded on evidence that could be corroborated— how and in what sense the lives of human beings have been improved by space exploration and showing, also, that these benefits outweigh the cost of space exploration.
I think that out of courtesy for Shakespeare the original quote from the play Julius Cesar could be mentioned but since it is a paraphrase of the quote and not the exact words spoken by Mark Anthony then I think it is not absolutely necessary to cite the source.