Explanation/Reference:
Explanation:
Answer option A is correct.
The fax machine is the encoder of the message.
The communication model shows the traversal of information between two hosts, known as the sender and the receiver. The key components of the model are as follows:
Encode: It is used to encrypt or code the message into a language that is understood by others.

Decode: It is used to decrypt the message back into the meaningful codes.

Message and feedback message: It is the output of encoding.

Noise: It is referred to anything, which interferes with the transmission and understanding of the

message.
Medium: It is the method used to convey the message.

In the communication process, it is the duty of the sender to send clear and complete information to the receiver so that it is properly received by the receiver, and for confirming that it is properly understood. The duty of the receiver is to make sure that the information received is understood and acknowledged properly. A failure in communication can negatively impact the project.
Answer option D is incorrect. The sender is the person sending the message.
Answer option B is incorrect. The medium is the telephone lines between the two fax machines.
Answer option C is incorrect. The transporter is not a valid term for the communication model.
Reference: "Project Management Body of Knowledge (PMBOK Guide), Fourth Edition" Chapter: Communications and Human Resources Objective: Communication Models and Effective Listening