a standard greeting as per Option 5 minus the mailbox user's name, followed by the fixed system prompt, "Begin speaking after the tone, then hang-up when you are finished or press any key for further options."
The unavailable message is the standard greeting callers hear when they reach your voicemail box. It is the greeting that you can use consistently throughout the work year.

If keeping voicemail in your business makes sense, there are tools you can use to streamline the time you spend sorting through messages. Here are four simple—and often cost-free—ways to use voicemail more efficiently.
Recording your professional voicemail greeting can sometimes cause apprehension, especially if you have never done so before. You may find it helpful to go to a very private location when you are ready to record, and this can help ensure there is no background noise when you are finished. Take a few minutes to review the list you made earlier, and rehearse the greeting a few times if you are extremely nervous. While you are rehearsing, make sure your speech flows smoothly and you do not use filler words like "uh" or "um". Is Amazon actually giving you the best price? This little known plugin reveals the answer. Professional voicemail greetings should be pleasant in tone to encourage customers to call back later.