A change key is designed to operate a single specific lock within a keyed system and is typically assigned to an individual user for limited access. In key control systems, which are important in organizational and Human Resource security management, different key types are used to control access levels. A change key provides the lowest level of access, ensuring that employees can only enter authorized areas relevant to their roles. This supports accountability, reduces security risks, and helps enforce workplace policies. Options A and C describe functions of master or grand master keys, which open multiple locks. Option D refers to control or core keys used for lock maintenance. Proper use of change keys helps organizations maintain structured access control and protect assets, personnel, and sensitive areas effectively.