Final answer:
Media commissions refer to the amount of client money that agencies spend on media purchases and other equivalent activities.
Step-by-step explanation:
The correct answer is B. Media commissions.
Media commissions refer to the amount of client money that agencies spend on media purchases and other equivalent activities.
For example, if an agency is responsible for buying advertising space for a client, they may receive a commission based on the amount of money spent on media purchases.