In What Way Was Japan Involved in World War I?​

In what way was Japan involved in World War I?​

A) ​Neutral observer.
B) ​Occupation of the Phillipines.
C) ​On the side of the Triple Entente to take control of German territories in Asia.
D) ​On the side of the Triple Alliance to take control of French territories in Southeast Asia.
E) ​Renewed war with Russia in violation of the Treaty of Portsmouth.