Which sentence could serve as a strong thesis statement for a research paper?

many books have been written about the civil rights movement.
voting is an important civil right.
martin luther king, jr., was born in atlanta, georgia.
the civil rights movement benefited americans of every race.

The most fitting answer for this question is the last one, "The Civil Rights Movement benefited Americans of every race." This statement introduces your topic and reveals your argument (that the movement was beneficial). The other statements are too narrow (options one and three) or broad (option two). Thesis statements cannot be too broad or narrow and need to summarize your paper in a succinct way. Hope this helps.