The interpersonal communication element of interference is anything that may prevent the receiver from completely understanding a sender's:

The interpersonal communication element of interference specifically refers to obstacles that hinder the effective transmission of a message from a sender to a receiver. When considering the choices, "Message" stands out as it embodies the overall content, intention, and meaning that the sender aims to convey. Interference can arise from various sources, such as noise (literal or figurative), emotional states, biases, or misunderstandings, which can distort or obscure the intended message. Thus, if interference occurs, the receiver may misinterpret or fail to grasp the sender's message fully, impacting the overall communication effectiveness.

The other options, while related to communication, do not encapsulate the wide range of factors that can obstruct understanding in the same way. Assertiveness refers to the sender's confidence in expressing their thoughts or feelings, demotion relates to a reduction in rank or status, and feedback pertains to the receiver's response to the message. These concepts, although important in communication contexts, do not specifically represent the completeness of the sender's message when interference occurs.