Determine the type of crystalline solid for each given material.

$($a$)$ a brick of pure nickel

a covalent network solid

an ionic solid

a metallic solid

a molecular solid

$($b$)$ a pinch of table salt

a covalent network solid

an ionic solid

a metallic solid

a molecular solid

$($c$)$ solid carbon dioxide $($attained from freezing carbon dioxide gas$)$

a covalent network solid

an ionic solid

a metallic solid

a molecular solid

$($d$)$ a diamond

a covalent network solid

an ionic solid

a metallic solid

a molecular solid