A) $ 30{}^\circ $
B) $ 25{}^\circ $
C) $ 50{}^\circ $
D) $ 60{}^\circ $
Correct Answer: B
$ \therefore $ $ \angle BOC=180{}^\circ -130{}^\circ =50{}^\circ $ Again, $ \angle BDC=\frac{1}{2}\angle BOC $ [angle at circle is half the angle at centre]
$ \Rightarrow $ $ \angle BOC=\frac{1}{2}\times 50{}^\circ =25{}^\circ $