If $\left|\overrightarrow{\mathrm{P}}+\overrightarrow{\mathrm{Q}}\right|=0$, then which of the options may be true? 

$\overrightarrow{\mathrm{P}}=-\overrightarrow{\mathrm{Q}}$

$\overrightarrow{\mathrm{P}}\&\overrightarrow{\mathrm{Q}}$ are perpendicular to each other

Angle between  $\overrightarrow{\mathrm{P}}\&\overrightarrow{\mathrm{Q}}$  is equal to ${180}^{\circ }$

One of the vectors has zero magnitude but the other vector has non-zero magnitude