The correct option is D Sanatorium
A sanatorium is an establishment for the medical treatment of people who are convalescing or have a chronic illness. For example, "Amidst the military hostilities, officials often viewed the stations as an emergency source of food for sanatoriums, military hospitals, and shelters for homeless children". Hence, Option D is correct. Among the rest of the options, asylum means an institution for the care of people who are mentally ill, hospital means an institution providing medical and surgical treatment and nursing care for sick or injured people, cemetery means a large burial ground, especially one not in a churchyard. These options do not express the intended meaning, hence incorrect.