C36: Consider a conduction electron in a metal crystal of cubic shape. The electron is free to move throughout the volume of the crystal, but cannot escape to the outside. How does the ground state of the electron E₁₁₁ change if the crystal is subject to high pressure?

1) E₁₁₁ decreases.

2) E₁₁₁ does not change.

3) E₁₁₁ increases.