b
(b) Given circuit can be reduced as follows
(\(C\) \(=\) capacitance of each capacitor)
The capacitor \(3\,C\), \(3\,C\) shown in figure can with stand maximum \(200\, V\).
So maximum voltage that can be applied across \(A\) and \(B\) equally shared. Hence maximum voltage applied cross \(A\) and \(B\) be equally shared. Hence max. voltage applied across \(A\) and \(B\) will be \((200 + 200)\) = \(400\, volt\).
