Darlene Finds the Speaker Uninteresting and Boring; She Turns to Her

Darlene finds the speaker uninteresting and boring; she turns to her smartphone to text her friends. What important principle does Darlene ignore?

A) Listening is the responsibility of both the speaker and the receiver.
B) Multi-tasking is inefficient and difficult to achieve.
C) Sources are liable for receiver receptivity.
D) Sources need to know whether and how clearly they are communicating their