Which of the following would be the most effective thesis statement for an informative speech? a. The causes of the Civil War were economic, social, and political. b. The North and South fought the Civil War for many reasons, some of which were the same and some different. c. While both sides fought the Civil War over the issue of slavery, the North fought for moral reasons while the South fought to preserve its own institutions. d. While both Northerners and Southerners believed they fought against tyranny and oppression, Northerners focused on the oppression of slaves while Southerners defended their own right to self-government.