The right of a municipality to install a water line underground across Owner A's property involves the acquisition of what?

The acquisition of subsurface rights is correct in this context because it pertains to the legal authority to use and modify the ground beneath the surface of the property. When a municipality installs a water line underground, it is operating below the surface level of Owner A's property, which inherently involves the subsurface rights.

Subsurface rights allow for the use of land beneath the surface, including the installation of utilities like water lines. This concept is crucial because property ownership does not just entail ownership of the surface but can extend to certain rights below it.

Surface rights refer to the ownership of the land itself, while air rights pertain to the space above the property. Water rights relate specifically to the ownership and use of water sources, such as rivers or groundwater. Therefore, while these other rights are important in property law, they do not apply in this scenario of installing an underground water line.

Understanding subsurface rights is essential for recognizing how municipalities can engage with property owners for public utilities, highlighting the balance between private ownership and public infrastructure development.