Where did Kunwar Singh join the rebellion of 1857 against the British?

The correct answer is A. Arrah.

Kunwar Singh was a zamindar (landowner) from Arrah in Bihar. He joined the rebellion of 1857 against the British in June 1857. He led a successful campaign against the British in Bihar and Uttar Pradesh. He was defeated by the British in 1858 and died in April 1858.

Option B, Patna, is incorrect because Kunwar Singh did not join the rebellion in Patna.

Option C, Bettiah, is incorrect because Kunwar Singh did not join the rebellion in Bettiah.

Option D, Varanasi, is incorrect because Kunwar Singh did not join the rebellion in Varanasi.