During the period of retreating monsoon, i.e. by the end of October south-west monsoon winds retreat from most of northern India. The low-pressure area lying over Northwest India is transferred to the middle of the Bay of Bengal by the end of October. As a result of these unstable conditions, severe cyclonic storms originate in the Bay of Bengal. These cyclonic storms strike along the eastern coast of India causing wide spread rain in the coastal regions.
Hence, option B is the correct answer.