Final answer:
The subject of the question is Business. It is asking about the percentage of target customers who will be exposed to a business' message given a certain combination of media.
Step-by-step explanation:
The subject of the question is Business. Specifically, the question is asking about the percentage of target customers who will be exposed to a business' message given a certain combination of media. This concept is related to marketing and advertising strategies, where businesses aim to reach their target audience through various media channels.