Among the four options, three objects/things have same properties. Find the odd one out.

Confluence Concourse Concentration Radiation

Radiation

Radiation shows the property of spreading while the rest three shows concentration at a point. [1]Confluence→The place where two rivers meet. [2] Concourse→Open part of a building. [3] Radiation →Sending out the rays. [4] Concentration →a large hall or space inside a building such as a station or an airport