Who is the most important leader in both houses of Congress?
the president pro tempore
the president of the Senate
the Speaker of the House
the Senate majority leader

The speaker of the house

Explanation:

is by far the more important and more powerful within the halls of Congress. This is particularly so because the Speaker is both the elected presiding officer of the House and the acknowledged leader of its majority party.

a is correct

hope this let me know if it is right