Explanation:

- The Azad Hind Fauj, also known as the Indian National Army (INA), was formed in 1942.

- Option 1: Singapore

- The INA was first officially established in Singapore by Captain Mohan Singh with Indian prisoners of war of the British Indian Army who had been captured by the Japanese in the Malayan campaign and at Singapore.

- This movement was later revived and led by Subhas Chandra Bose.

- Singapore played a key role due to its strategic location and large Indian immigrant population.

- Correct Answer: Singapore

- Option 2: Tokyo

- Tokyo was a significant place where the Japanese extended support to the INA, though it was not the formation site.

- Option 3: Berlin

- Berlin had seen Bose's efforts in seeking support from the Axis powers, but the INA was not formed there.

- Option 4: Rangoon

- Rangoon (now Yangon) was an important city during the INA's operations, but not its location of formation.

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