select the sentence from the text that explains the cause of Weeping Rock's unusual water flow.

a
As the plants grow out of the rock face, they give the illusion that they are hanging in the air.
b
The shortest trail leads to one of the popular destinations: Weeping Rock, a cliff face with a hanging garden.
c
The water was unable to continue down, so it traveled horizontally.
d
Vegetation grows in shaded areas of the cliff with water coming through the rock.