Final answer:
A NOTAM with the term APROX is valid until further notice, indicating it remains in effect without a specific end date until a new notification supersedes it.
Step-by-step explanation:
A NOTAM (Notice to Airmen) that includes the term APROX (Approximately) is typically an advisory notice that may not have a specific end date, but rather provides information that may affect the National Airspace System. The correct answer to 'A NOTAM that has the term APROX is valid until' would be b) Until further notice. This means that the NOTAM will remain in effect until a new NOTAM is issued to cancel or replace it, or until a specified condition changes.