What is the term used for the notice issued after all responses to an INREQ are negative?

The term used for the notice issued after all responses to an INREQ (Information Request) are negative is indeed ALNOT. An ALNOT, or Alert Notice, is utilized in search and rescue operations to inform other units or agencies that a search is underway for an aircraft that is unresponsive or missing. After exhausting all means of locating the aircraft, and receiving no affirmative responses, issuing an ALNOT ensures that all relevant parties are alerted about the situation, promoting coordinated efforts in search and rescue.

In contrast, URGENT refers to a priority classification for certain types of information but does not specifically relate to the scenario of negative INREQ responses. VFR NOTAM pertains to Notices to Airmen that provide information to pilots operating under Visual Flight Rules, and is unrelated to the search and rescue context of an INREQ. SAR Alert signals the initiation of a search and rescue operation, but it would occur as a result of an ALNOT, not as the notice issued after negative responses to an INREQ. Therefore, the correct term highlighting the context of search efforts following negative responses is indeed ALNOT.