Francenie Was Digging a Trench to Install a Drainage Pipe

Francenie was digging a trench to install a drainage pipe along her property line and she accidentally tunneled under a small area on her neighbor's property. The entry onto the neighbor's property:

A) cannot be a trespass because it was beneath the surface of the land.
B) is not a trespass unless there was some actual damage to the neighbor's land.
C) is a trespass.
D) is not a trespass because Francenie was under the reasonable belief that she owned all of the land on which she was digging.