Instructions 20Q Game: These are similar to full games, but for quizzes larger than 20 questions it will randomly select 20 questions from within the set. This is a quick way to get in some studying of a topic.     
Identify the US President that fits the following statement, or led during the following event:

"Master of the Senate"
Herbert Hoover
Richard Nixon
Lyndon B. Johnson
Ulysses S. Grant