An example of an intrapersonal barrier in the decoding of a message is option b: Sarah finds her mind drifting during a lecture as she thinks about her upcoming trip to Hawaii. Intrapersonal barriers refer to internal factors that affect an individual's ability to understand and interpret a message. In this case, Sarah's thoughts about her upcoming trip to Hawaii are distracting her and preventing her from fully focusing on the lecture. This internal distraction hinders her ability to decode and understand the message being delivered.
On the other hand, one of the elements of the linear model of communication is option c: psychological/semantic/physical/interpersonal noise. In the linear model, noise refers to any interference or disruption that affects the transmission or reception of a message. This noise can be psychological (internal distractions), semantic (misunderstandings due to language barriers or jargon), physical (external disturbances such as loud sounds), or interpersonal (conflicts or tensions between communicators). Noise can distort or hinder the communication process and make it difficult for the intended message to be accurately decoded by the receiver.
Remember, intrapersonal barriers are internal distractions that affect an individual's understanding of a message, while noise in the linear model of communication refers to any interference or disruption that affects the transmission or reception of a message.