Answer:
C. Written communication
Explanation:
Written communication involves communicating or interacting through writings using circular, journals, letters, reports as the medium. It involves conveying a message through written words or symbols. In this case, its important for the marketing manager to use written communication in disseminating the information he wants to his workers because it's often permanent and verifiable, thus creating a permanent record of evidence. Information written can be stored for long periods, and the marketing plan by the manager is something that may involve a long period of time. Therefore, the written communication can be referenced whenever there's need to go back to the plan to check specific details.