What element are diamonds composed of

diamonds are carbon based and have a giant covalent structure

Explanation:

This is what gives diamonds its strength and rigidity.

Diamonds are different from graphite due to the way the atoms are arranged

option b is true

Explanation:

Since the equilibrium constant Kp is defined as the ratio of [products]/[reactants] ( option c is false) , then Kp units depends on the order of reaction of the reactants and the number of reactants and products involved ( option a is false).

for example if the concentration is expressed as M (molarity)

Keq= [A]/[B]*[C] then Kep has as units 1/M

Also t a specific temperature , the equilibrium constant represents the relationship between concentrations of reactants and products , and its fixed at constant temperature (option b is true).