Final answer:
In the communication process model, 'feedback' is the receiver's response that indicates reception and understanding of the message, aligning with option c). It is crucial for maintaining effective communication.
Step-by-step explanation:
In the communication process model, "feedback" refers to the receiver's response to the sender's message. It acts as an indication that the message has been received and understood, whether it is through a formal reply or a symbolic behavior. Feedback helps to control and coordinate actions within the communication process.
It is essential for maintaining effective communication and can either counteract or amplify the original message, similar to how feedback mechanisms work in biological systems. In this context, feedback is most accurately represented by option c) the receiver's formal response or symbolic behavior indicating that they received the message.