Why Are the Participants in a Circle During a Round

Why are the participants in a circle during a round table discussion?

A) So they can see and interact with each other when no one is seated in a superior position.
B) Because they sit around a table.
C) So no one is seated in a different place and can keep up the discussion.
D) So no one is left out of the conversation.
E) Because they sit around a table and no one is left out of the conversation.