How does the electron structure of an isolated atom differ from that of a solid material?

Group of answer choices

A) There is no difference in electron structure between an isolated atom and a solid material;

B) An isolated atom has an electron band structure. Solid materials have discrete electron energy states.

C) The valence electrons of each atom disappear in the bulk material.

D) An isolated atom has discrete electron energy states. Solid materials have electron band structures.