Final answer:
Screening telephone calls primarily involves selecting which calls to forward to staff members by understanding the call's purpose, which manages communication flow and prioritizes urgent issues efficiently.
Step-by-step explanation:
The primary goal of screening telephone calls is C) Selecting which calls should be forwarded to which staff members through an understanding of the purpose of the call.
This process involves a receptionist or assistant answering the phone and determining the nature and urgency of the call. Based on this information, they decide whether to forward the call to the appropriate staff member, handle the inquiry themselves if it's within their competence, or take a message. Screening is a crucial task in managing a professional environment, as it helps in prioritizing calls, ensuring that critical issues are addressed promptly and efficiently, and maintaining order in the flow of communication.