Final answer:
Security guards should never be without a radio or cellular phone to ensure their safety, and allow for quick communication in case of emergencies or observations that require immediate attention.
Step-by-step explanation:
The question pertains to the safety protocols for security guards concerning communication while on patrol. The correct answer is E) guards should never be without a radio or cellular phone.
This is because it is imperative for security personnel to maintain constant communication for their own safety and for the effective performance of their duties. In case of an emergency or need for immediate assistance, having a radio or cellular phone allows for quick response and support. Furthermore, having access to communication devices helps in reporting any observations or incidents that require attention.