Which of the Following Does Not Physically Loosen Rocks on the Surface

Multiple Choice

Which of the following does not physically loosen rocks on the surface?

A) Water contracting as it freezes
B) Crystals of salt and other minerals that exert an outward force on fractures
C) Roots that pry apart fractures as the root grows in size
D) Joints that form when rock pressures are released
E) Rodents and other burrowing organisms