The correct options are
A Japan had to step back due to the USA attack.
B Due to monsoon, the terrain was difficult to travel.
As the Second World War was ongoing, Japan was attacked by the USA. The Japanese troops had to step back and the help provided to the INA also stopped. INA did not have basic amenities like food, arms, and ammunition. Moreover, because of the monsoons, the terrain became extremely difficult to travel. Imphal could not be captured by the INA.