22. If G represents the modulus of rigidity (or shear modulus of elasticity), E is the modulus of elasticity, and v is Poisson's ratio, which of the following statements is true for any homogeneous material?
 

a. G is independent of E.
b. G is 0.4E.
c. G is 0.5E
d. G depends on both E and v.
e. None of these.