Explanation:

- Option 1: Mosca

- Gaetano Mosca was an Italian political scientist.

- He is known for his work on political theory and sociology.

- Correct Answer: "The Ruling Class" was written by Gaetano Mosca.

- Option 2: Michels

- Robert Michels, a sociologist, is famous for his "iron law of oligarchy" theory.

- He did not write a book titled "The Ruling Class."

- Option 3: Dahl

- Robert Dahl was an American political theorist.

- Known for his theories on democracy and political pluralism.

- He did not author "The Ruling Class."

- Option 4: Rose

- Richard Rose is a political scientist with works focused on comparative politics.

- He didn't write "The Ruling Class."

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