What are the most common types of security threats?

The correct answer highlights the most prevalent forms of security threats that security personnel are likely to encounter in their daily operations. Theft involves the stealing of property, which directly impacts a company's assets and can lead to significant financial loss. Vandalism refers to the intentional destruction or defacement of property, compromising safety and security in the environment. Physical altercations encompass any violent interactions that could pose risks not only to property but also to the safety of individuals present. Together, these threats represent actionable items that security personnel must be prepared to handle, making them crucial aspects of security training and procedures.

The other options do not accurately represent the primary security threats. Cyber threats, while important, are just one type of threat and often not as immediately visible as physical threats like theft or vandalism. Complaints from employees and employee performance issues, while they can affect workplace morale and safety indirectly, do not directly correspond to physical security threats that need real-time intervention by security personnel. Therefore, "theft, vandalism, and physical altercations" represents the core set of threats that security guards are trained to identify and mitigate.