which statement best describes a chemical property related to the particles that make up a material

A. nickel is a good conductor of electricity because the metallic bonds between its atoms allow electrons to move freely.
B. demand is a hard substance because its atoms are joined together by covalent bonds.
C. metallic bonds between its ions cause silver to be a highly malleable material.
D. chlorine is highly reactive with other elements because its atoms have 7 valence eletrons.