The various ways in which a message can be sent, ranging from one$-$on$-$one in$-$person meetings to Internet message boards, are called $\_\_\_\_\_.$

The various ways in which a message can be sent, ranging from one$-$on$-$one in$-$person meetings to Internet message boards, are called $\_\_\_\_\_.$

meeting points

message transmitters

communication channels

personalized anchors