If A and B are square matrices of order n, then $\mathrm{A}-\mathrm{\lambda I}$ and $\mathrm{B}-\mathrm{\lambda I}$ commute for every scalar $\mathrm{\lambda }$, only if

• A

  AB = BA

• B

  AB + BA = O

• C

  A = -B

• D

  none of these