In terms of message-distribution objectives, which of the following is a definition of reach?

• A. It refers to a measure of the intensity of a schedule based on repeated exposures to the medium.
• B. It refers to total size of the audience for a set of ads or an entire campaign.
• C. It refers to the total number of unique people exposed to a medium during a given period of time.
• D. It refers to the duration of an advertising message or campaign over a given period of time