The "minuscule" is the best option to describe a small house or room.
Here's why:
Microscopic: refers to something very small, invisible to the eye. This is not an appropriate term for a house or room, which are generally visible.
Macroscopic: refers to something large enough to be seen with the eye. This is also not appropriate for a house or room, as these are typically not considered large.
Minuscule: refers to something very small, but still visible to the eye. This is the most appropriate term for a house or room that is considered small.
Diminutive: means small and delicate. While this could potentially describe a small house or room, "minuscule" is a more precise and direct term.
Therefore, "minuscule" is the best option to describe a small house or room.