Correct option is D
The one-word substitute for "A place where water is collected and stored for future use" is "Reservoir."
· Meanings of the given words:
· Reservoir: A large natural or artificial lake used as a source of water supply.
· Aquarium: A tank or pool in which aquatic animals and plants are kept.
· Resort: A place that is frequented for holidays or recreation.
· Sanatorium: An establishment for the medical treatment of people who are convalescing or have a chronic illness.