Correct option is (C) ∠DOC
Since, equal chord subtends equal angles at the centre of the circle.
Also, \(\angle AOB=\) Angle subtend by chord AB at the centre of the circle (O).
\(\angle DOC\) = Angle subtend by chord CD at the centre of the circle (O).
and AB = CD
\(\therefore\) \(\angle AOB=\) \(\angle DOC\)