Answer: D. To help your classmate learn the main developments in communication, write concise, organized notes about the background, technology, and people involved in each major advancement.
Step-by-step explanation:
Since the student has been out for the entire unit on communication and will have to take a unit exam when the students gets back to school, the summary to the student should be concise, simple and understandable.
The note should be about the background of communication, technology used in communication and the people that are involved in the major development.
Therefore, the correct option is D.