Answer:
The best statement that explains an effect of Reconstruction legislation on the United States using Source 1 and Source 3 is (B) It expanded the role of the federal government in protecting citizens' rights and promoting racial justice. Source 1 discusses the various Reconstruction amendments that were passed, such as the 13th, 14th, and 15th amendments, which granted rights to African Americans, while Source 3 discusses the role of the federal government in enforcing these rights. Both sources emphasize the importance of the federal government in promoting equality and civil rights during the Reconstruction era. Therefore, (B) is the most accurate statement that describes the effect of Reconstruction legislation.