Which of the following is a requirement for legislation to become law?

Legislation typically requires approval from the President to become law at the federal level in the United States. Once a bill is passed by both chambers of Congress, it is sent to the President, who has the authority to sign it into law or veto it. If the President signs the bill, it becomes law. If the bill is vetoed, Congress can override the veto with a two-thirds majority vote in both houses, allowing the bill to become law despite the President's objections.

In contrast, while the Supreme Court plays a significant role in interpreting laws and ensuring they align with the Constitution, it does not have a direct role in the legislative process or in the enactment of legislation. Approval from state governors is not a requirement for federal legislation, as governors handle state legislation rather than federal laws. Lastly, while public opinion can influence legislation, a referendum where the public directly votes on certain measures is not a standard requirement for legislation to become law at the federal level.