Let $A$ and $B$ be two square matrices of order $3$ and $AB = O_{3}$, where $O_{3}$ denotes the null matrix of order $3$. Then,

• A
  must be $A = O_{3}$ and $B = O_{3}$
• B
  if $A \neq O_{3}$, then $B$ must be $O_{3}$
• C
  if $A = O_{3}$, then $B$ must be $O_{3}$
• D
  it is possible that $A \neq O_{3}$ and $B \neq O_{3}$