Which of the following leaders has the title equal to the President of the Senate when the Vice President is not present?

The correct choice reflects that the President pro tempore of the Senate serves in the absence of the Vice President. This role is established in the Constitution and makes the President pro tempore the presiding officer over the Senate during its sessions when the Vice President, who is typically the President of the Senate, is not available.

The President pro tempore is usually a senior member of the majority party, and their duties typically include presiding over Senate sessions, maintaining order, and managing legislative business. This position is significant in ensuring that the Senate functions effectively and maintains continuity in leadership.

The Speaker of the House, while a significant leadership position, is exclusive to the House of Representatives and does not hold any authority in the Senate. The Senate Majority Leader is primarily responsible for leading the majority party within the Senate but does not have the formal responsibilities of the presiding officer when the Vice President is absent. The Congressional Whip's role is to assist party leadership in managing party discipline and ensuring member attendance, but they do not preside over the Senate sessions. Thus, the President pro tempore is the only title among the choices that directly corresponds to the role assumed in the absence of the Vice President.