Communist Party
noun
The idea of everyone together sharing property between them comes from which party? That's the Communist Party.
きょうさんとう
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
最初に気づいたのは、彼が共産党員だということでした。
The first thing I noticed was that he was a member of the Communist Party.