In the figure $ \angle \mathrm{AOC}$ and $ \angle \mathrm{BOC} $form a pair of
supplementary angles
The explanation for the correct answer.
Find the relation between the angles.
It is shown in the figure that, are the angles on a straight line and form a linear pair.
The sum of the angles of the linear pair is .
Therefore the angles are supplementary angles.
Hence option is the correct answer.