A compound is formed by two elements $\mathrm{M}$ and $\mathrm{N}.$ Element $\mathrm{N}$ forms hexagonal closed pack array with $2/3$ of the octahedral holes occupied by $\mathrm{M}.$ The formula of the compound is:

• A

  ${\mathrm{M}}_4 {\mathrm{N}}_3$
• Correct answer
  B

  ${\mathrm{M}}_2 {\mathrm{N}}_3$
• C

  ${\mathrm{M}}_3 {\mathrm{N}}_2$
• D

  ${\mathrm{M}}_3 {\mathrm{N}}_4$

Hence, the correct answer is option: 'B'.