Which of the following roles is part of the executive branch?

The role of the president is a key component of the executive branch, making this choice the correct answer. The executive branch is primarily responsible for enforcing laws and administering the functions of the government, and the president serves as the head of this branch. This position involves implementing policies, directing the nation's foreign affairs, and overseeing the various federal agencies that function to carry out governmental duties.

In contrast, the roles mentioned in the other choices pertain to different branches of government. Supreme Court justices belong to the judicial branch, which interprets laws and administers justice. Senators and House Representatives are members of the legislative branch, responsible for making laws. Therefore, they do not fit the category of the executive branch, which is why the president stands out as the correct answer.