Answer:
D. A room that is made of glass to allow exposure to sunlight
Explanation:
A solarium is a room in which you are surrounded by glass, allowing for the sunlight to seep in, as if you are outside while being indoor. It's kind of like a planetarium, except instead of being surrounded by stars and planets, you're submerged into sunlight and the beauty of outside!
I hope this helps!
-No one
