Final answer:
The highest priority issue that the principal should address in reviewing the school's safety and security practices is unauthorized access to the school through unattended entrances. Option D is the correct answer
Step-by-step explanation:
When reviewing the school's current safety and security practices, the principal should make it the highest priority to address the issue of visitors being able to use any of several unattended entrances to get into the school. This is a significant security vulnerability as it allows unauthorized individuals to enter the school premises without proper monitoring or identification. By implementing measures to control and secure entrances, such as installing surveillance cameras, hiring security personnel, or implementing a visitor check-in system, the school can greatly enhance its safety and security.