The correct answer is: Monsoon season.
The monsoon season is the wettest time of year in Manipur, and it is also the time when flash floods are most likely to occur. This is because the monsoon rains cause rivers to swell and overflow their banks, which can lead to sudden and destructive floods.
The winter season is the driest time of year in Manipur, and it is also the time when flash floods are least likely to occur. This is because there is very little rain during the winter, so rivers are not as likely to swell and overflow their banks.
The dry season is the second-driest time of year in Manipur, and it is also the time when flash floods are less likely to occur than during the monsoon season. However, it is still possible for flash floods to occur during the dry season, especially if there is a sudden and heavy downpour of rain.
Throughout the year, flash floods can occur in Manipur, but they are most likely to occur during the monsoon season.