In the event of a bomb threat received via telephone, which piece of information is most crucial for a security guard to try and obtain from the caller?

1. The exact location of the bomb, the time it is set to detonate, and the type of explosive.
2. The caller's name, phone number, and reason for making the threat.
3. The specific demands or grievances of the caller and their organization.
4. The caller's background noise, voice characteristics, and gender.