Extension cords used in fire alarm systems should not be:

Extension cords used in fire alarm systems should not be fastened with staples, hung from nails, or suspended by wire because doing so can damage the cord and create a safety hazard. When extension cords are improperly secured in this manner, it can lead to pinching or crushing of the cord, which can cause insulation breakdown and increase the risk of electrical shock or fire. Proper installation and routing of electrical cords are crucial for maintaining safety and ensuring that fire alarm systems function effectively. Additionally, this practice violates National Fire Protection Association (NFPA) guidelines and other applicable electrical codes aimed at ensuring that electrical installations are safe and reliable. Hence, option B accurately highlights a critical safety concern in the installation and use of extension cords in fire alarm systems.