The statement not true about graphite is:
Graphite is denser than the diamonds
The explanation for the correct option
(B) Graphite is less dense than diamonds
The explanation for incorrect options
(A) The three valence electrons of carbon take part in bond formation and the fourth electron is free and mobile and hence can conduct electricity.
(C) The thermodynamic stability of graphite is more than that of diamond
Therefore, graphite is denser than diamonds, option (B) is correct.