15. Are responsible for maintaining the extensive heating, air-conditioning, refrigeration, and ventilation systems in hospitals
A. Health Care Administrator
B. Hospital Maintenance Engineer
C. Nurse Manager
D. Medical Librarian

The person responsible for maintaining the extensive heating, air-conditioning,  refrigeration and ventilation systems in hospitals is hospital maintenance engineer (option B).

Explanation:

Hospital maintenance engineers are trained to operate air conditioning systems, boilers, pumps and compressors in the hospital area, performing manual and automatic operation. Additionally, they are in charge of checking, adjusting, maintaining, turning on and off the equipment they control.  

Other functions related to the general maintenance of the hospital areas are in charge of the maintenance engineer and his staff. Their work must be constant and must ensure the presence of maintenance personnel for 24 hours in the hospital.

Regarding other options:

    A. Health Care Administrator : corresponds to the administrative director of the hospital.

    C. Nurse Manager : is in charge of supervising the nursing staff, establishing roles and work schedules.

    D. Medical Librarian: is in charge of handling all bibliographic and digital material related to health issues