Final answer:
The correct response for an administrative assistant when receiving a call from an unfamiliar voice or number is to answer professionally.
Step-by-step explanation:
When receiving a call from an unfamiliar voice or number, the correct response for an administrative assistant is to answer professionally. It is important to maintain a polite and professional tone while speaking with callers, even if their voice or number is unfamiliar. By answering professionally, the assistant can provide a positive image of the company and ensure effective communication.