The number of independent elastic constants required to

The number of independent elastic constants required to define the stress-strain relationship for an isotropic elastic solid is _____.

1. G & μ are independent.
2. E & μ are independent.
3. G & E & μ are independent.
4. None of these

Elastic constants are required to obtain relationship between stress & strain, There are 4 elastic constants.
E, μ, G, & E
But E & μ are independent.