Who were the members of the "Big Four"?

Woodrow Wilson of the United States, David Lloyd George of Britain, Vittorio Emanuele Orlando of Italy, and Georges Clemenceau of France.

Vittorio Emanuele Orlando

Georges Clémenceau

Woodrow Wilson

Proof:

Proof from an passage on the internet,

"The "Big Four" leaders in Paris in 1919 for the World War I peace-treaty talks: Prime Ministers David Lloyd George of Great Britain, Vittorio Orlando of Italy, Georges Clemenceau of France, and President Woodrow Wilson."